How is the analysis for syphilis. Syphilis test: how to donate blood

Laboratory tests have significantly expanded the capabilities of modern medicine. They are considered especially valuable in the diagnosis of infectious diseases, in particular syphilis. What is the name of the analysis for syphilis, what preparation does it require, according to what rules is it carried out? We will talk about the features of laboratory diagnosis of this common venereal pathology in our review.

Features of syphilis

Despite the fact that in the Middle Ages, syphilis (the former name of the infection is lues, from the Latin "infection") terrified cities and villages, causing the death of tens of thousands of people, today this disease is considered, albeit unpleasant, but quite even curable. Is it really?

Syphilis is a specific venereal disease caused by pathogenic spirochetes, pale treponemes. Infection with them occurs during close contact with the patient; unprotected sex occupies the leading positions in the spread of infection.

A few decades ago, vertical and blood transfusion transmission routes remained widespread. The first is associated with infection of the fetus in the womb from a sick mother. The second - with the transfusion of infected donor blood to the recipient. Currently, such routes of infection are rare, since both pregnant women and persons who decide to become donors need to be repeatedly screened for syphilis.

From the moment of infection until the first signs of infection appear, it can take from 10 days to six months (on average 1 month).

• The clinical manifestation of the primary form of the disease is syphiloma (chancre) - a small painless seal or sore at the site of penetration of treponema into the body. More often it develops on the skin of the external genital organs.
• After a few weeks, the syphiloma completely resolves, and the person feels completely healthy. However, after 1-2 months, the main symptom of secondary syphilis appears - a polymorphic rash on the skin in the form of soft pink spots. Skin manifestations are a sign of the spread of the pathogen throughout the body. The duration of this stage is several years.
• If secondary syphilis has not been treated, the final, tertiary form of infection develops. Treponema actively affects all organs and tissues, gummas appear on them - dense nodes that eventually collapse and leave rough connective tissue scars.

Thus, primary and even secondary forms of syphilis diagnosed at the initial stage are successfully treated with antibiotics. Late variants of pathology lead to irreversible destructive changes in the body, dangerous complications from the nervous and reproductive systems. They are difficult to correct and can cause disability of the patient.

The success of therapy for this chronic infectious disease largely depends on timely diagnosis. What tests are taken for syphilis, and what they can show: let's figure it out.

Indications for testing

Laboratory tests for syphilis today can be passed in any private or public laboratory. Among the indications for the test:

• screening examination of all pregnant women (the analysis must be submitted twice: when registering and for a period of 30-32 weeks);
• examination of persons wishing to become blood donors;
• dispensary examination of certain categories of working people (for example, civil servants, military personnel, doctors, catering workers);
• comprehensive diagnostics of patients before a planned operation or hospitalization for inpatient treatment;
• an indication of a history of unprotected sexual intercourse;
• the presence of clinical manifestations of syphilis.

Note! Today anyone can check their health at home. To do this, it is enough to purchase a rapid syphilis test at a pharmacy.

Preparation for the examination

Depending on the type of examination, the patient needs to donate venous or capillary blood.

Read also on the topic

What is congenital syphilis, what are its signs and methods of treatment?

One drop of biological fluid from a finger is enough to carry out an express test. Special preparation for such tests is not required, the only recommendation is not to smoke for 30-40 minutes before taking blood and not to drink alcohol during the day.

The requirements for analysis using venous blood are somewhat broader. In addition to limiting bad habits, patients are advised to:

• give up intense physical activity 2-3 days before the study;
• on the eve of the test, eat easily digestible food;
• follow the rules of good sleep;
• on the day of the examination, you can only drink non-carbonated water: blood from a vein is given strictly on an empty stomach.

What tests are taken to detect infection?

The basis of laboratory diagnostics of venereal pathology is made up of tests aimed at detecting specific antibodies synthesized by the bone marrow in response to the damaging effect of treponema pallidum.

Since the main biological substrate for the diagnosis of syphilis is blood serum (less often - plasma), all analyzes are combined under the general name of serological tests, which are divided into treponemal and non-treponemal.

Features of non-treponemal tests

Non-treponemal tests are used for screening and assessing the effectiveness of the treatment performed by the venereologist.

Non-treponemal analyzes are based on interactions not with the causative agent of syphilitic infection, but with lipid complexes arising from the destruction of its cells. During the chemical reaction of a specific reagent with antibodies in the body, AG-AT (antigen-antibody) complexes are formed, which precipitate and are available for evaluation with the naked eye. The reaction is considered:

• negative (-) if there are no flakes and any types of sediment;
• weakly positive / doubtful (+, ++), if small flakes are found;
• positive (+++, ++++) if large flocs can be seen in the sediment.

It is important to know that non-treponemal tests retain false negative values ​​for 1-1.5 months after infection. Primary syphiloma - the first sign of the classic course of syphilis - is usually 7-28 days ahead of positive test values.

Despite the high speed of obtaining examination results and the cheapness of many non-treponemal tests, their effectiveness remains low. These tests are able to diagnose primary syphilis in 75-90%, secondary - in 100%, and tertiary - in no more than 30-50% of cases. To confirm the diagnosis of syphilis, it is necessary to carry out specific tests, called treponemal in medicine.

Wasserman reaction

The Wasserman reaction (RW) is a well-known and time-tested test for determining the causative agent of syphilis in the blood. It is based on obtaining blood serum with inactivated own complement. Then the prepared biomaterial is divided into two parts: one of them is treated with a syphilitic antigen, the other with a cardiolipin one.

The results are assessed by the rate of hemolysis (membrane rupture and complete destruction) of erythrocytes:

• full (-) - negative result;
• short delay (+) - dubious result;
• partial delay (++) - weakly positive result;
• long / absolute delay in hemolysis (+++, ++++) - a positive result.

RW becomes positive 2-3 weeks after the onset of primary syphiloma. The effectiveness of the test in the secondary form of the disease is 100%, in the tertiary form –75%.

Features of treponemal tests

Treponemal analyzes are used for in-depth diagnosis of venereal infection, among them are:

• RIF (analysis based on the application of the fluorescence method);
• RIT (reaction of assessment of immobilization of living Tr. Pallidum);
• ELISA (enzyme-linked immunosorbent assay);
• RSK (a reaction in which the immune system binds complement);
• RPGA (reaction of passive "gluing" of shaped elements);
• method of immunoblot.

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When is a false positive test for syphilis possible?

Specific and highly sensitive methods of serodiagnostics are called treponemal. They allow the detection of antibodies (immunoglobulins) directly to the antigenic structures of the causative agent of syphilis - treponema pallidum.

RPGA

RPHA test is prepared on the basis of erythrocytes of animals sensitized with treponema pallidum antigen. It is added to the patient's serum and after 1 hour the results are evaluated:

• center point (-) - negative reaction;
• unfinished ring (+) - doubtful;
• a ring of cells that have undergone agglutination (++, +++, ++++) - a positive result.

Linked immunosorbent assay

Immunoassay is a highly sensitive and specific method for serodiagnosis of syphilis. Based on the interaction of human antibodies, labeled enzymes, and laboratory reagent. Allows you to accurately determine the presence of IgM (a marker of acute inflammation), IgG (a marker of chronic inflammation) and IgA (immunoglobulin contained in fluids - breast milk, saliva). In addition to examining patients, it is used to monitor therapy.

Immunofluorescence tests allow the diagnosis of syphilis with high sensitivity even before its first symptoms appear. They show positive results already 5-7 days after infection. Antibody fluoresceins combine with specific serum antibodies to create luminous complexes:

• background staining (-) - negative result;
• slightly noticeable glow (+) - weakly positive reaction;
• pale green glow - ++;
• green glow - +++;
• bright green-yellow glow - ++++.

RIT

RIT (Tr. Pallidum immobilization reaction) is a method used to diagnose latent forms of venereal disease. This laborious test is based on the phenomenon of cessation of physical activity of living treponemes when interacting with the "AG + AT" complex. Under laboratory conditions, live syphilis pathogens are added to the patient's purified serum. The results are assessed according to the following scheme:

• immobilized bacteria that the researcher observes through the eyepiece of the microscope make up less than 20% - a negative result;
• 21-30% (++) - doubtful;
• 31-50% (+++) - weakly positive;
• over 50% (++++) - positive.

Note! For RIT, it is important that the patient takes antimicrobial drugs no later than four weeks before blood sampling.

Immunoblot

Immunoblot is the most innovative and reliable method for diagnosing the described pathology, excluding false positive and false negative results. Like other tests, it is based on an antigen-antibody complex interaction. The serum of the test person is applied to a prepared membrane coated with the antigens of the pathogen. If specific IgM and IgG are found in it, stripes appear on the test system. In the future, the laboratory assistant assesses the location of these stripes and the intensity of their color.

Decoding the results

In the complex diagnosis of syphilis, it is important to carry out several tests that complement each other. The table below shows the interpretation of the examination results depending on the indices of non-treponemal and treponemal analyzes.

Non-treponemal	Treponemal	Possible results
—	—	The man is healthy, he did not have syphilis.
		Primary syphilis at an early stage of development (1 week after infection).
		Successfully cured primary syphilis 7-14 months after therapy.
		Sometimes: HIV-infected patients with active syphilis.
+-	—	False positive result.
—	+	Initial forms of infection some time after successful treatment.
		The primary form of syphilis.
		Secondary form of infection.
		Late (characterized by the formation of gum) syphilis in the absence of adequate therapy.
		Syphilis patients with autoimmune pathologies, neoplasms, concomitant infectious processes.
+	+	Untreated patients with syphilis at any stage.

Syphilis is a disease that can cause complications that are difficult for the patient's life and health. But it develops very slowly, over several years, and this means that a person has enough time to be examined and to defeat the infection in his body in a timely manner.

Higher medical education, venereologist, candidate of medical sciences.

Content

One of the most common sexually transmitted diseases is syphilis. Modern medicine is able to cope with it, but if the patient is not treated, he will face a slow and painful death with many symptoms. For this reason, it is very important to have a regular blood test for syphilis. This approach helps to avoid serious health problems among both young people and adults. Due to prevention awareness, the incidence of this venereal disease is slowly but steadily declining.

What is syphilis

It would be nice for everyone to know more about syphilis. It is a chronic systemic venereal infectious disease that affects the skin, mucous membranes, nervous system, bones and internal organs with a sequential change in the stages of the disease. The causative agent is the bacterium pale treponema (Treponema pallidum), which has a negative effect on the human body. Previously, the infection was called "Gallic disease".

Scientists have proven that pale treponema affects not only a person who has been diagnosed with syphilis, but also affects the heirs. Experts explain this by the fact that the bacterium affects the chromosomes. The disease proceeds in three stages:

1. Primary. The formation of syphilitic ulcers (hard chancre) and inflammation of the nodes of the lymphatic system are observed.
2. Secondary. A rash begins to form on the skin. There is a high risk of infecting other people.
3. Latent. There is no symptom, but the patient remains contagious. If the disease is diagnosed during pregnancy, there is a high risk that the infection will be congenital, i.e. passed from mother to fetus.

In about 30 percent of patients, specialists diagnose a tertiary disease. The infection severely affects the skin, important organs, brain and bones. As of 2014, 26 people out of 100 thousand of the population in Russia suffered from this venereal disease. To diagnose syphilis, you will need to donate blood for tests. A general blood test for this venereal disease carries little information, therefore it is not used for diagnosis.

Diagnosis of syphilis

In order to be tested for the presence of pale treponema, a person needs to undergo an external examination and laboratory diagnostics, as well as a blood test for syphilis. The analysis will enable doctors to detect specific (IgG and IgM) and non-specific antibodies or the bacterium itself in the blood. The choice of diagnostic method depends on the stage of the disease.

To detect specific antibodies, the causative agent of syphilis is used, i.e. pale treponema. This test is called treponemal. Experts find nonspecific antibodies in the material released from the destroyed treponema cell - this is a nonspecific antiphospholipid, reaginic or RPR test (RPR). The described methods are not the only ones, you can check the blood for the presence of syphilis pathogens, you can use tests for:

• polymerase chain reaction;
• passive agglutination reaction;
• immunofluorescence reaction;
• Wasserman reaction;
• immunoblot for syphilis (immunoblotting).

These studies are widely used to diagnose and monitor the course of the disease. With a preliminary diagnosis, a blood test is taken on an empty stomach. There are cases when, after cure, the patient's blood is taken again for research, and the result is positive. Among specialists, it is known as a dubious test for syphilis. To cleanse the blood, doctors prescribe certain procedures.

Diagnostic indications

There are several indications for which it is imperative to undergo appropriate studies. This is especially true for a pregnant woman, who must take a detailed analysis for the presence of the causative agent of a venereal disease three times: the first is given when she is registered, the second - at a period of 31 weeks, the third - before childbirth. If a pregnant woman has a positive test for syphilis, then the baby is also prescribed examinations after birth. Other indications:

• The patient suspects that he has syphilis. Many patients are afraid of a rash on the genitals.
• There was an intimate relationship with a person with syphilis.
• The patient is in prison.
• A person has a desire to become a donor and he needs to donate sperm and blood.
• The need to pass a medical commission for employment. This applies to all those who get a job at a school or kindergarten, hospital, cafe, sanatorium, grocery store, etc.
• If the patient has enlarged lymph nodes (lymphadenitis) or has been diagnosed with an undetermined fever.
• A person takes drugs.

Preparation

Taking an analysis for the presence of pale treponema is a crucial moment, because the patient's life is directly dependent on the results obtained. The preparation time for this event is measured not in days, but in weeks. It is necessary to adhere to several recommendations:

• Eliminate fatty foods 24 hours before testing. In this way, the patient will prevent a false positive result due to the optical phenomenon associated with fat.
• The study for syphilis is really only on an empty stomach, so experts recommend not to eat for about 7 hours before undergoing the examination.
• It is strictly forbidden to smoke and drink alcohol one day before going to the doctor. This can make it difficult for professionals to assess the response.
• Do not take antibiotics a week before donating blood.

How to take a test for syphilis

A general blood test to determine this sexually transmitted disease is considered meaningless - in order to recognize syphilis, patients need to undergo a comprehensive clinical and laboratory examination. The following samples can be taken for the study:

• blood from a vein and a finger;
• discharge of a hard chancre (ulcer);
• areas of regional lymph nodes;
• CSF (cerebrospinal fluid).

To exclude or confirm the diagnosis of syphilis, the analysis is chosen directly by the specialist - his preference will be based on the period of development of the disease. In this case, the result can be obtained in a day, and in some cases even in a few weeks. The specific terms depend on the chosen diagnostic method, the equipment of the medical institution and how busy its laboratory is. In general, it does not matter how long it takes to find out the results of a study, the main thing is what result it will show.

Types of analyzes

At the initial stage, a bacterioscopic technique is often used, which is based on identifying the pathogen (treponema pallidum) under a microscope. A serological test for syphilis is widely used - this type of test is based on the determination of antibodies and microbial antigens produced by the body in biological material. Bacteriological research is not carried out due to the fact that the pathogen grows very poorly in artificial conditions on a nutrient medium. All methods for detecting treponema pale are divided into two large groups:

1. Direct, which directly detect the microbe itself:

• RIT test. Experts infect the rabbit with the test material.
• Dark field microscopy. With its help, treponema is detected against a dark background.
• PCR (polymerase chain reaction). This technique detects areas of the genetic material of the microorganism. This type of research takes the longest time.

2. Indirect, or serological. They are based on the detection of antibodies to the microbe, the production of which is carried out by the body in response to infection. Among serological studies, two groups are distinguished:

Treponemal:

• immunoblotting;
• ELISA, or enzyme-linked immunosorbent assay;
• RPHA, or passive hemagglutination reaction;
• RIT / RIBT, or treponema immobilization reaction;
• RSKt, or binding of complement to treponemal antigen;
• RIF, or the reaction of immunofluorescence.

Non-treponemal:

• Bladder cancer, or microprecipitation reaction;
• RSKk, or the reaction of complement binding with cardiolipin antigen;
• RPR, or plasma rapid reagin test;
• sampling with toluidine red.

Direct tests

The use of direct tests convincingly proves the presence of pathogens when they are detected with a microscope. The likelihood of syphilis in this case reaches 97 percent. True, microbes can be detected only in 8 out of 10 patients, for this reason a negative test does not completely exclude the presence of the disease. This kind of diagnosis is carried out in the primary and secondary periods, when there is a skin rash or chancre. In the samples separated from these infectious elements, the specialist looks for the causative agents of the disease.

More effective, but at the same time more complex and expensive analysis, is the detection of pathogens after their preliminary treatment, the so-called. fluorescent antibodies. The latter are substances that "stick" to treponemes and form their glow in the field of view of the microscope. The sensitivity of the method begins to decrease when treating rashes and ulcers with antiseptics, long duration of the disease and after treatment.

The biological diagnostic technique for RIT is considered highly specific but expensive. The result has to wait a long time until the infected rabbit develops a disease. Currently, this method of research is almost not practiced, although it is considered the most accurate of all known. A good blood test for detecting the genetic material of the causative agent of a sexually transmitted disease is PCR. Its only limitation is its relatively high cost.

Serological methods

When conducting a serological test, microbial antigens and antibodies are determined. The latter are produced in biological materials as the body's response to infection. An indirect research method is based on their identification, which is:

• non-treponemal;
• treponemal.

Non-treponemal tests

The most well-known of the RSKk analyzes is the Wassermann reaction (RW). This method of rapid diagnosis (express analysis) is based on a similar response of antibodies from the patient's blood to cardiolipin, which is obtained from a bovine heart, and treponemes themselves. The result of this interaction is the formation of flakes. In Russian medical institutions, this type of research is widely used. Its downside is its low specificity.

A false positive test for syphilis can occur in blood diseases, tuberculosis, systemic lupus erythematosus, menstrual bleeding, pregnancy, after the birth of a baby, and in some other cases. For this reason, with a positive RW, more accurate research methods are used. After infection with a sexually transmitted disease, the reaction gives a positive result after a couple of months. With secondary syphilis, it will be positive in almost all patients.

The microprecipitation reaction has a similar mechanism - this method is replacing the Wasserman test in Russia. The technique is inexpensive, easy to implement, and good in that it gives a quick assessment. With her, false positive results can also appear. Both of these tests are used by specialists as screening tests. Bladder cancer will become positive a month after the formation of a hard chancre. For this study, blood is taken from a finger.

RPR is another type of antigen (cardiolipin) reaction. This technique is used for:

• suspected syphilis;
• donor screening;
• screening the population.

Another method in this category of tests is the toluidine red assay. All of these methods are used in order to assess the effectiveness of treatment. They are considered semi-quantitative, i.e. increase during recurrence of the infection and decrease when the patient is recovering. Negative test results in this category with a high degree of probability indicate that the subject is not sick. For this reason, they are used to assess cure - the first test is taken 3 months after the end of the course of treatment.

Treponemal

• suspected syphilis;
• diagnostics of latent forms;
• positive screening test (microprecipitation reaction);
• retrospective diagnosis, when the patient has already suffered an illness;
• recognition of a false positive screening result.

The highest quality (highly specific and highly sensitive) methods include RIF and RIT. The disadvantages of these methods are complexity, duration, the need for trained personnel and modern equipment. In many cured people, treponemal tests remain positive for many years, so they are not used as a criterion for cure:

• RIF becomes positive only 2 months after infection. If it is positive, there is a high probability of the presence of the disease, if it is negative, the person is healthy.
• RIT is often used when bladder cancer is positive in order to confirm or rule out the disease. It is highly sensitive. Due to this, it is possible to confirm or deny the disease with great accuracy. True, the result will become positive only 3 months after infection.

Western blotting is more sensitive than RIF, while it is inferior to RPHA. This technique is used infrequently and in most cases for the diagnosis of pale treponema in newborns. The listed methods are not suitable for screening (rapid detection of the disease), because become positive later than the microprecipitation reaction. More modern highly informative research methods are RPGA and ELISA:

• The ELISA test gives a positive result 3 weeks after infection. The disadvantage of this technique is that the result is sometimes unreliable. A false positive reaction can occur with metabolic disorders, systemic disease and in children who are born with sick mothers.
• The RPHA method gives a positive result when a hard chancre appears (primary seropositive syphilis) - about a month after infection. It is especially valuable in the study of congenital, latent and late forms of the disease. For the accuracy of the diagnostic measure, RPHA must be supplemented with at least one treponemal and one non-treponemal test. The disadvantage of RPHA is the maintenance of a positive reaction for a long time, therefore it is not used as a criterion for cure.

Both of the methods described by you for diagnosing treponema pale are inexpensive - they are performed in large quantities and give a quick result. These tests can be used to confirm or deny a diagnosis. The shortcomings of methods included in the serological category have led to the emergence of more advanced types of research. They do not give errors, but they are expensive and are rarely used - these are mass spectrometry, gas chromatography.

Deciphering the analysis for syphilis

None of the currently proposed methods for diagnosing a sexually transmitted disease does not guarantee a 100% result. In any case, there is an error that reaches 10%. Decoding of specific and non-specific serodiagnostic tests:

Method name	Description	Decoding the results
Microreaction of precipitation	This study is indicative after 1 month after infection. Blood from a finger is examined, but cerebrospinal fluid is sometimes used.	A positive result (antibodies in titer range from 1: 2 to 1: 320) does not yet mean that the patient is sick - the final result is confirmed by passing additional tests. A negative reaction is a consequence of the fact that: the subject is not sick; the patient is sick, but the disease is at an early stage of development.
Wasserman reaction (PB, RW)	With this method, objective information can be obtained at least 6 weeks after infection. It is possible to talk about the presence of pathology if the antibody titers fluctuate between 1: 2-1: 800.	The results in RV are assessed by mathematical signs: "-" - no disease; "+" Or "++" is a weakly positive reaction; "+++" - positive; "++++" is strongly positive.
	This technique is relevant at very early stages of the development of the disease, but the optimal period for testing is 6-8 weeks after infection. The study requires venous or capillary blood.	A positive outcome of the study is expressed by pluses from one to four ("+" - "++++"). Connective tissue defects and pregnancy often cause false results, which are indicated by a “-” sign.
	In the course of this study, a little blood is removed from the subject from a vein or finger, then it is mixed with the erythrocytes of a rooster or ram. This type of testing has a higher sensitivity, because he is able to confirm the presence of the pathogen for a long time after the treatment. It takes no more than 1 hour to receive an answer. Patients can check themselves with RPHA 4 weeks after a possible infection: at earlier stages, antibodies are not produced in the required volume.	How long the infection has been in the blood can be judged by the titers: if their value is not more than 1: 320, then the infection occurred relatively recently; the higher the titers, the longer the pale treponema is in the patient's body.
	It is considered one of the most reliable methods for diagnosing the described disease. ELISA began to be used at the end of the last century. It will be indicative already 21 days after infection. A positive result by 98-99% indicates the presence of a venereal disease. Often, ELISA is used after performing nonspecific testing or in combination with some specific tests.	The ELISA test provides an opportunity to find out the stage of the disease by identifying a specific group of antibodies in the patient's blood: If the sample contains IgA antibodies, but no IgG, IgM, then no more than 14 days have passed since the treponema entered the body. If IgM and IgA were detected, but IgG was absent, infection occurred about 28 days ago. If the sample contains all of the listed antibodies, then this indicates that more than 1 month has passed since infection. If there is no IgA in the sample, but IgG and IgM are present, then after infection a long period of time has passed or the therapy of the disease was successful.
	It is one of the most popular types of disease diagnostics. It makes no sense to use it in the early stages of infection, but after the 12th week, the results of RIBT testing will be 99% reliable. It is used for suspected syphilis of internal organs, neurosyphilis, or in combination with non-specific techniques. If the patient took durant (long-acting) antibiotics, then he will have to wait at least 25 days after the end of treatment. Antibiotics from the water-soluble category require less time to be eliminated from the body - about 7-8 days.	Blood for research is taken from a vein (on an empty stomach), and the result is interpreted as a percentage of immobilization: If the immobilization level exceeds 50%, the test is considered positive. If the level of immobilization is not higher than 20%, then the test is negative. In all other cases, retesting is carried out.
Immunoblotting	This method of detecting ailment is one of the newest at the present time. They turn to her if other methods have given a dubious result. At the same time, not all clinics carry out such testing, because it's expensive.	When carrying out immunoblotting, the specialist is able to detect even the minimum content of antibodies in the sample taken. In the end, the diagnosis will have an accuracy of almost 100%.
Laboratory analysis	The cost of this study is the lowest. The result can be found out after half an hour. To carry it out, a sample is taken from the subject from erosive and ulcerative defects located in the genital area. The affected areas are initially wiped with saline to protect the damaged area from harmful microorganisms. Then, using a special loop, the surface is irritated for several minutes until a white-transparent liquid is obtained, which is then transferred to a transparent glass - sometimes mixed with saline.	A positive result is spoken of when typical treponemas are identified, having from 8 curls or more. If the result turns out to be negative, then the procedure is repeated - sometimes several times.

False positive analysis

The question often arises as to whether the results could be wrong? Yes, especially when using non-treponemal tests. The causes of acute false positive tests when using bladder cancer are:

• trauma, poisoning;
• stroke;
• pneumonia;
• myocardial infarction;
• acute infectious diseases.

If there are controversial results, then specialists to clarify the diagnosis resort to treponemal serological tests. It should be borne in mind that chronic false positive tests often occur when:

• tuberculosis;
• leptospirosis;
• brucellosis;
• malignant tumors;
• cirrhosis of the liver;
• diabetes mellitus;
• sarcoidosis;
• rheumatic diseases;
• infectious mononucleosis, etc.

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Attention! The information presented in the article is for informational purposes only. The materials of the article do not call for self-treatment. Only a qualified doctor can diagnose and give recommendations for treatment, based on the individual characteristics of a particular patient.

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A syphilis test detects the presence of antibodies against the bacteria that cause syphilis in the tissues or blood of the body.

Syphilis is a sexually transmitted disease, that is, through sexual intercourse, oral sex or kissing.

What tests are taken for syphilis?

Tests to detect the disease include:

• a special test for the presence of human-produced antibodies in the body;
• rapid analyzes for plasma reagins;
• enzyme immunoassay (the newest blood test for syphilis).

All test results for syphilis show the presence of antibodies to the bacteria that cause the disease.

Analyzes are carried out in order to:

• detection of syphilis disease;
• control over the treatment of the disease.

All pregnant women are invited, in the early stages of pregnancy, to undergo a routine examination and be tested for syphilis.

If the disease is neglected, it is possible:

• severe heart disease;
• spinal injury;
• blindness;
• brain disorders;
• of death.

Taking tests for syphilis requires serious preparation.

You must tell your doctor:

• whether you are taking antibiotics or other medications;
• are you allergic to medications (antibiotics and anesthetics);
• do you have problems with spontaneous bleeding;
• about your pregnancy state.

If syphilis is found, it is necessary to avoid sexual intercourse until you have completed the full course of treatment. Your sexual partner should also undergo a complete examination.

A general blood test for syphilis is performed, as a rule, within one week, however, modern equipment has reduced this time to one day.

Decoding a general blood test for syphilis shows:

The most commonly used term in venereology is "serological blood test".

This method is commonly used:

• when studying antigens or antibodies in blood serum;
• to establish a blood group;
• to determine the presence of antibodies to certain types of viruses and bacteria (syphilis, toxoplasmosis, hepatitis, chlamydia, measles, rubella, mumps, cytomegalovirus, herpes simplex, mycoplasmosis).

Modern diagnostics divides serological analysis into two groups:

• non-treponemal (non-specific) analyzes;
• treponemal (specific) analyzes.

Usually, four weeks after infection, a positive test for syphilis is detected.

If the analysis shows a positive result, then, obviously, the person is sick with this venereal disease.

A false positive test for syphilis occurs in about five percent of patients.

Possible reasons for a false positive test:

• systemic lesions of the connective tissue (scleroderma, dermatomyositis, rheumatoid arthritis, vasculitis, lupus erythematosus);
• infectious lesions (hepatitis, tuberculosis, mononucleosis, intestinal infections);
• inflammation of the heart (myocarditis, endocarditis);
• pregnancy;
• diabetes;
• recent vaccination;
• the use of drugs, alcohol.

Reasons for possible false negative results:

• a large number of antibodies in the blood;
• the analysis was taken before the possible appearance of antibodies;
• the analysis was taken for chronic syphilis (the amount of antibodies in the blood is significantly reduced).

A false (erroneous) analysis for syphilis can occur in about 10% of patients, but with repeated retakes of the analysis, this error will certainly be noticed and corrected.

Note that every pregnant woman is tested for syphilis during pregnancy.

Moreover, she does it three times:

• when registering;
• in the second trimester;
• in the third trimester.

With this test procedure, the disease can be detected in a timely manner.

The minimum price for taking tests for syphilis starts from 1.500 rubles.

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Blood tests for syphilis

The earlier and more accurately syphilis is detected, the easier the treatment is and the higher the likelihood that it will go smoothly for the patient.

The goal for all laboratory tests is the same: to make a diagnosis unambiguously and quickly. But none of the modern high-tech analyzes for syphilis gives the result unambiguously and with 100% accuracy. Old methods are being improved, new ones are invented, but until now, in clinical practice, doctors always have to use a combination of several different tests for syphilis. Doctors cannot rely on the result of any one.

There are so many types of analyzes for syphilis that it is impossible to understand all the abbreviations on the fly:

For the first time, it was possible to identify the disease using a laboratory reaction in 1906. This is the merit of the German scientist August Wassermann, after whom the reaction is named. Much time has passed since then, the method is outdated and is not used in practice, but the diagnosis of syphilis is still firmly associated with the analysis of RV.

A person may need to be tested for syphilis for a variety of reasons. The very first reason that comes to mind is when an infection is suspected, and in practice it is not the most common. In this case, it is important to understand that the infection has an incubation period (from the moment of infection to the formation of a hard chancre) and a primary seronegative period (a hard chancre in the first three weeks) - at this time the tests will be negative. Therefore, if the fears are serious, the tests are repeated after a few weeks.

People who do not suspect any infection are required to be tested for syphilis more often. This usually happens when hiring (the analysis is included in the medical book) and during periodic medical examinations (medical examinations). Even without fail, blood for syphilis is donated:

• donors,
• women in the first weeks of pregnancy - twice, when registering with an antenatal clinic and in a maternity hospital a few weeks before childbirth,
• patients before surgery or any other medical invasive interventions (FGDS, bronchoscopy, etc.).

At the end of the article, we answered the most frequent questions of people faced with the diagnosis of syphilis. There is no time to read the details about research methods - scroll down.

All types of tests for syphilis

There are 2 main groups of research methods for syphilis: direct and indirect.

• The direct method is a study in which the infection itself is looked for in the biomaterial - individual representatives of the pathogen as a whole, or their pieces - DNA.
• Indirect methods (serological tests) are tests in which they try to detect antibodies to the causative agent of syphilis in the blood. The logic is as follows: if an immune response characteristic of some infection is found, then there is the infection itself, which caused this immune response.

Direct methods are the most reliable: if the bacterium is "caught red-handed", then the presence of the disease is considered proven. But pale treponema is difficult to catch, and negative test results do not exclude the presence of infection. It makes sense to carry out these studies only in the presence of rashes and only with an early form of syphilis - up to two years of illness. Those. it is impossible to determine latent syphilis or its late forms with these methods, therefore in clinical practice they are rarely used and only to confirm other analyzes.

Direct methods include: Dark-field microscopy, Infection of laboratory animals, PCR.

1. Dark-field microscopy (TPM) - examination of pale treponema under a microscope. The material is taken from hard chancre or eruptions. The method is cheap and quick, and detects syphilis at the very beginning of the primary period, when blood tests for syphilis are still negative. But bacteria in the rash, which are in small quantities, can easily not get into the scraping. Plus, pale treponemas can be easily confused with other inhabitants of the oral cavity, anal canal, etc.
2. Infection of laboratory animals is a very expensive and painstaking method, it is used only in research practice.
3. PCR is a relatively new method, it looks for DNA infection. Any tissue or fluid that may contain pale treponemas is suitable for research: blood, urine, prostate secretions, ejaculate, scraping from skin rashes, from the genitourinary tract, oropharynx or conjunctiva. The analysis is very sensitive and specific. But complicated and expensive. It is prescribed in case of questionable results of other tests.

Indirect methods, they are also serological reactions, are the basis of laboratory testing for syphilis. It is these methods that are used for mass screening of the population, for confirming the diagnosis and monitoring treatment. Indirect research methods are divided into non-treponemal and treponemal tests.

Non-treponemal tests are noticeably cheaper. For their implementation, not the protein antigen itself, which is specific for syphilitic treponema, is used, but its replacement - the cardiolipin antigen. These tests are highly sensitive but poorly specific. This means that such tests will indicate everyone who has syphilis and more: healthy people can also have false positive results. They are used for mass screening of the population, but in the case of a positive result, they must be confirmed by more specific tests - treponemal. Non-treponemal tests are also very useful in assessing the effectiveness of treatment: with effective treatment, the volume of antibodies in the blood decreases, and, accordingly, their titer decreases (we will talk more about these titers a little further). The most reliable result of these non-treponemal tests will be during early syphilis, especially during the secondary period.

Non-treponemal tests include:

• The Wasserman reaction (RW, aka RV, or RSK) is already outdated and not used, but because of its strong association with the disease, any tests for screening the population for syphilis are often called so. If you see a record "RV analysis" in the direction from the doctor - do not be embarrassed, the laboratory will probably understand everything correctly and will do RPR.
• The microprecipitation reaction (MR, aka RMP) is a simple and cheap test to determine syphilis. Previously used as the main non-treponemal test, but has now given way to the more convenient and objective RPR test.
• Rapid plasmareagin test (RPR test) is a quick, simple and convenient test for mass screening of the population and control of treatment. It is the main non-treponemal test used in Russia and abroad.
• TRUST is a more modern modification of the RPR test. In another way, it is referred to as the RPR test with toludine red. In Russia, it is used only in a small number of laboratories.
• VDRL - This analysis is similar in reliability to the RMP and is also inferior to the RPR. It has not found wide application in Russia.
• The USR test (or its modification - the RST test) is a more advanced VDRL test, but it is also used extremely rarely in Russia.

Treponemal tests are performed with treponemal antigens. They are more specific, and therefore more carefully weed out the healthy from the sick. But their sensitivity is lower, and such tests can miss a sick person, especially at an early stage of the disease. Another feature is that treponemal tests appear later than non-treponemal tests, only three to four weeks after the appearance of a hard chancre. Therefore, they cannot be used as screening devices. The main purpose of treponemal tests is to confirm or deny the results of non-treponemal tests.

Treponemal test results will also remain positive for several years after successful treatment. Because of this, they are not used to monitor the effectiveness of treatment, and they are also not relying on the results of these tests unless they are confirmed by non-treponemal tests.

Treponemal tests include:

• RPHA (or its more modern modification - TPPA, TPNA) is a passive hemagglutination reaction. The main treponemal reaction now used abroad and in Russia. A simple and convenient test for detecting syphilis antibodies in the body.
• ELISA (anti-Tr. Pallidum IgG / IgM) - enzyme-linked immunosorbent assay, aka ELISA with an English abbreviation. This test can be performed with both cardiolipin antigen and treponemal antigen. It can be used both for screening and as confirmation. In terms of reliability, it is not inferior to RPHA and is also the recommended treponemal test to confirm the diagnosis of syphilis.
• Immunoblotting is a more expensive advanced ELISA test. Used only in doubtful cases.
• RIF is the reaction of immunofluorescence. Technically difficult and expensive analysis. It is secondary, it is used to confirm the diagnosis in doubtful cases.
• RIBT (RIT) - a reaction of immobilization (immobilization) of pale treponema. This reaction is complex, time consuming to execute and difficult to interpret the result. In some places it is still used, but gradually fades into the background, giving way to RPGA and IFA.

Decoding of serological tests for syphilis:

Algorithm for the diagnosis of "syphilis"

Any diagnosis consists of three main pillars of medicine: history (medical history), clinical manifestations (symptoms) and laboratory examination. If the doctor, according to the patient's story and by external examination of his body, suspects syphilis, he prescribes a set of tests (or a set of serological reactions - DAC). It necessarily includes 1 non-treponemal test (RMP or RPR) and 1 treponemal test (RPHA or ELISA). If the results of these tests differ, an additional alternative treponemal test (ELISA or RPGA) is performed. This is the simplest scheme. In case of doubtful indicators, depending on the situation, the doctor prescribes other diagnostic methods.

Rapid test for syphilis, or how to determine syphilis at home

There is a self-administered syphilis test. It can be freely purchased at a pharmacy, the average cost is 200-300 rubles. The principle of disease definition is similar to non-treponemal RPR. Manufacturers claim high accuracy, but in reality it is low, no more than 70%.

The algorithm of actions during the check resembles a pregnancy test, only blood is used instead of urine. A drop of blood is applied to the indicator, and the result appears within 10-15 minutes. 1 strip - test negative, 2 strips - test positive. We do not recommend this diagnostic method. If you have doubts about syphilis, it is better to see a doctor right away, or at least an independent laboratory. It will come out a little more expensive and longer, but much more accurate.

Deciphering the results for syphilis: pluses, crosses and titles.

The further tactics of the doctor depend on the results of certain tests. The results of screening analyzes are expressed either in crosses (pluses), or in a separate record:

4 or 3 crosses - a positive result, further testing for syphilis is necessary using other diagnostic methods. 2 or 1 cross - a dubious result, it is recommended to repeat the result after 10 days.

0 crosses - negative result, no syphilis was found.

In the case of a positive and doubtful reaction, an additional study of the taken blood is carried out: diluting it from 1: 2 to 1: 1024 and adding a drop of cardiolipin antigen to each blood titer. The result is recorded the maximum titer at which the reaction occurred: the greater the dilution, the greater the titer value, the higher the number of pale treponemas in the blood. But the main task of determining the titer is not to calculate the degree of blood contamination, but to monitor the success of the treatment: the treatment is considered effective if the titer drops by 4 times in 4 months. By the end of treatment, non-treponemal test results should be negative.

The highest sensitivity of screening tests is observed in the secondary period of syphilis (100%), slightly less in the primary (86%) and even less in the tertiary (73%).

Important nuances in the diagnosis of syphilis:

1. False positive results are possible during tests. They are especially common during screening. If you have never had syphilis, and the tests are positive, you should not panic right away, you need to do at least one more alternative analysis.
2. There are also false negative results. If there is a suspicion of syphilis, then it is better to repeat the analysis after a few weeks.
3. Cured syphilis remains positive on treponemal tests for several years or life.

The most common questions about tests for syphilis

How to get tested for syphilis for free?

To do this, you need to contact the polyclinic at your place of residence and visit your local doctor, who will give a referral for analysis. Testing for syphilis is free for all residents of the Russian Federation under the compulsory medical insurance policy.

Where can i get tested for syphilis anonymously?

Analyzes can be taken anonymously in any paid laboratory; dermatovenous dispensaries often offer this service themselves. Also, it is possible to test for syphilis at home using express tests that are sold at the pharmacy. However, it must be remembered that such a test does not give an accurate result, and if you suspect syphilis, you should consult a doctor.

How many days after sexual intercourse can you donate blood for syphilis?

After 1-1.5 months. If an infection has occurred, the test for syphilis will be positive no earlier than seven to ten days after the appearance of a hard chancre, or 4-5 weeks after infection. This period may be longer, so if the results are negative, the analysis should be repeated after 2 weeks.

Where do they get blood for syphilis?

Blood for syphilis is taken more often from a vein, but it can also be taken from a finger. It depends on the type of analysis.

Preparation. How to get tested for syphilis?

Before donating blood for syphilis, you must not eat for four hours - blood must be donated on an empty stomach. In addition, alcohol should not be consumed 12 hours before the test. This is important because alcohol damage to the liver can trigger false positive tests.

How much is the average test done for syphilis?

The results are usually available the next day. Conducting express tests takes no more than 30 minutes.

What analysis is taken for syphilis and what is it called?

For screening, when there is no suspicion of the disease, either bladder cancer (microprecipitation reaction) or RPR (rapid plasmareagin test). Sometimes these screening tests are called the Wasserman reaction.

If there are any real suspicions or doubts, they are never limited to one analysis. At the same time, one of the screening groups (RMP or RPR) and one of any of the more specific testing groups (RPGA or ELISA) are performed, then they act depending on the results and the patient's history.

Could a syphilis test be wrong?

Maybe! The probability of error of different methods depends primarily on the period of the illness and the general condition of the organism.

Non-treponemal tests are most sensitive at the height of the disease - in the secondary period. Due to their low specificity, they often give false positive results. This can happen due to fever, flu or other infectious disease, recent vaccinations, chronic diseases, and a number of other reasons.

Treponemal tests are more sensitive in the later period. They can also give false positive results, but only if there are pathogenic bacteria similar to pale treponema in the body that cause other diseases: non-venereal pint treponematosis (rare in Russia) or Lyme disease (transmitted through a tick bite).

False negative test results are possible for all diagnostic methods. They depend on the body's immune response: no response - no response to syphilis. This is possible in HIV-infected people, as well as those who are immunocompromised for other reasons. In addition, there is a reverse reaction: overproduction of antibodies, the "prozone" effect, in which there are so many antibodies that they prevent each other from reacting with the antigen. The result is a false negative result.

Can general tests show syphilis?

Syphilis cannot be determined by either a general blood test or a biochemical one. A general urine test or a regular vaginal smear will not show it either. All studies for syphilis are highly specialized and each has its own name. By any other analysis, it is impossible to calculate whether a person has syphilis or not. But what will other tests show if a person is sick with syphilis? Let's take a look at each of them:

Complete blood count: shows the main blood cells - erythrocytes, leukocytes, platelets. At the end of the primary and at the beginning of the secondary period, a person's leukocytes can rise, and ESR, an indicator of inflammation, can also increase. These are very nonspecific indicators, simply indicating that the body is fighting a bacterial infection. Otherwise, the blood test will correspond to the general condition of the body.

Biochemical blood test: shows the work of the liver, kidneys, heart, pancreas and other organs. If syphilis has not yet struck these organs, and they are working properly, the blood test will be normal.

General urine analysis: shows the work of the kidneys and the endocrine system, as well as the general condition of the body. If there are no acute or chronic diseases of these systems, the analysis will be normal.

Vaginal smear: determines if there is an inflammatory or oncological process, as well as dysbiosis. You cannot put syphilis on such a smear.

Back to the section "Syphilis" back to the section "Syphilis"

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What are the tests for syphilis, their decoding

The analysis for syphilis is done using a variety of methods for detecting the pathogen. With the development of pathology, a large number of specific signs appear. In order to establish an accurate diagnosis, the patient is examined comprehensively. A general blood test is not very informative, it is not used to diagnose a venereal infection.

Types of research and biomaterials for analysis

Various techniques and biomaterials are used to detect the disease. In the early stages, syphilis is determined using a bacterioscopic test. The samples are examined under a microscope. The device allows you to detect strains of the pathogen. Serological tests are performed later. Thanks to them, antigens and antibodies to the disease are detected in the samples.

Methods for determining a genital infection are divided into 2 categories:

• Direct, revealing a pathogenic microorganism. These include: dark-field microscopy, RIT-analysis (infection of rabbits with biomaterial for research), PCR method - polymerase chain reaction (with its help, the genetic elements of the pathogen are found).
• Indirect (serological) detects antibodies to the pathogen. They are produced by the immune system as a response to infection.

Serologic techniques are divided into 2 categories: treponemal and non-treponemal.

Non-treponemal, including: toluidine red test, RSK analysis, RPR-test, blood test by rapid bladder cancer method.

Treponemal, combining: immunoblotting, RSK test, RIT analysis, RIF study, RPGA test, ELISA analysis.

The information content of infection tests is different. More often they do the main types of tests for syphilis, which include serological methods. For patients requiring examination, the doctor prescribes tests individually.

Biomaterial for research

To identify pale treponema, a pathogen that looks like a spiral and causes syphilis, samples are taken:

• venous blood;
• cerebrospinal fluid (secretion from the spinal canal);
• the contents of the lymph nodes;
• ulceration tissue.

If it is necessary to conduct tests for the detection of syphilis, blood is donated not only from the cubital vein, but also from the finger. The choice of biomaterial and the method of research is influenced by the severity of the course of the infection and the equipment of the diagnostic center.

Direct research

Convincing evidence of syphilis is the identification of infectious agents under a microscope. In this way, the pathogen is found in 8 out of 10. A negative result in the remaining 2 patients does not mean that they are not infected.

The study is done at the primary and secondary stage (stage) of the disease, which is characterized by the appearance of rashes on the skin and syphilis (ulceration) on epithelial tissues or mucous membranes. Pathogens that cause venereal disease are found in the discharge from the lesions.

More precisely, a complex test, denoted as RIF - the reaction of immunofluorescence, copes with the definition of treponemes. The sample for research is pretreated with fluorescent antibodies. The compounds capable of glowing stick together with bacteria. Examining samples under a microscope, in case of infection, the laboratory assistant sees sparkling pathogens.

The test is used for early diagnosis of the disease. The longer the disease lasts, the lower the sensitivity of the research methods. In addition, it falls after the treatment of rashes and ulcers with antiseptics and in patients who have undergone treatment. Occasionally research gives false negative and false positive results.

RIT analysis is a highly accurate method for detecting syphilis. When conducting a test, the results have to wait a long time. Until the infected rabbit shows signs of infection. The test is used very rarely, despite the fact that it is super accurate.

With the help of polymerase chain reaction for syphilis, the genetic elements of pathogens are determined. The only drawback of PCR is its high cost.

Non-treponemal tests

These blood tests help to detect antibodies that appear in response to cardiolipin, a compound related to the general structure of the membranes of pathogens.

Wasserman reaction (PB or RW)

The most famous study for syphilis is the Wasserman reaction. RV is included in the category of complement fixation reactions (CACs). New RSC methods have significant differences from traditional RW. But they are designated, as before, by the concept of "Wasserman reaction".

The immune system synthesizes antibodies (markers) in response to the invasion of treponemes. They are detected in a blood test for syphilis using the Wasserman reaction method. A positive RW result confirms that the subject is infected.

Hemolysis reaction - RV analysis index. With it, 2 substances interact: hemolytic serum and ram erythrocytes. Serum is made by immunizing a rabbit with ram erythrocytes. The activity of the biological fluid is reduced by heating.

RV indicators depend on whether hemolysis has passed or not. Hemolysis occurs in the sample free of markers. In this case, a reaction to antigens is impossible. Complement is spent interacting with sheep erythrocytes. When there are markers in the sample, the compliment reacts with the antigens. In this case, hemolysis does not occur.

The components for RW are measured in equal amounts. The sample containing serum, antigen and compliment is warmed up. Lamb erythrocytes and serum are added to the sample. It is kept at a temperature of 37 degrees until hemolysis occurs in the control sample, which contains saline instead of antigen.

For carrying out RV use ready-made antigens. The titers and the technology of their dilution are indicated on the packages. A positive RW result is indicated by crosses. The finished test results are indicated as follows:

• ++++ - the most positive (hemolysis was delayed);
• +++ - positive (hemolysis is significantly delayed);
• ++ - weakly positive (hemolysis partially delayed);
• + - doubtful (hemolysis was delayed slightly).

With negative PB, hemolysis was completely carried out in all samples. But in some cases, they receive false positive data. This happens when cardiolipin is incorporated into cells. Defense mechanisms do not produce markers to the "native" cardiolipin.

However, exceptional situations occasionally arise. Positive RW is found in uninfected people. This is possible if the patient has suffered a serious illness caused by viruses (pneumonia, malaria, tuberculosis, liver and blood pathologies). Positive RV occurs in pregnant women. This is due to the fact that the immune system is overly weakened.

If there is a suspicion that the test result for syphilis is false positive, the patient is examined additionally. The problem is that this infection cannot be detected by a single clinical laboratory test. Some research gives false indicators, which can be both negative and positive.

A detailed analysis for syphilis helps to obtain reliable data. Thanks to him, a true diagnosis is established: they prove the infection or exclude it. In addition, the extended test allows you to stop the development of infection, exclude unnecessary therapy.

RSK and RMP

When testing for syphilis, the traditional Wasserman reaction is rarely used. Instead, the RSC method is used. The test gives a positive result 2 months after infection. In the secondary form of the disease, it is positive in almost 100% of cases.

The method of microprecipitation (RMP) is a study with a mechanism similar to the Wasserman reaction. The technique is simple to implement. It is carried out quickly. For research, blood for syphilis in this case is donated from a finger. The technique gives a positive result 30 days after the appearance of the syphilis. Research errors are not excluded. False positive data are obtained against the background of: exacerbated infections, pneumonia, heart attack, stroke, intoxication.

Leads to erroneous tests:

• tuberculosis;
• Benier-Beck-Shauman disease;
• rheumatoid diseases;
• diabetes;
• cirrhosis;
• brucellosis;
• leptospirosis;
• mononucleosis.

Having found a dubious analysis for syphilis, treponemal studies are done. They help to clarify the diagnosis.

RPR and toluidine red test

The Plasma Reagin Method (RPR) is another analogue of the Wasserman reaction. It is used when necessary:

• screening asymptomatic individuals;
• confirm syphilis;
• examine donated blood.

The toluidine red test, like the RPR, is performed to assess the dynamics of drug therapy. Their indicators fall when the disease recedes, and increase when the pathology recurs.

Non-treponemal tests show how much the patient has been cured. Getting negative results for syphilis indicates that the disease has completely receded. The first examination is done 3 months after the course of therapy.

Treponemal studies

Highly productive tests are performed using treponemal antigens. They are made when:

• a positive result was obtained with the RMP method;
• it is necessary to recognize erroneous data arising from screening tests;
• suspect the development of syphilis;
• you need to diagnose a covertly current infection;
• it is necessary to conduct a retrospective diagnosis.

RIF and RIT tests

In many treated patients, treponemal tests of samples give positive results for a long time. They cannot be used to judge the degree of effectiveness of treatment. RIT and RIF are supersensitive tests. Thanks to them, they get reliable data. These analyzes are laborious, they require a decent amount of time and the availability of advanced equipment. They are able to be carried out by qualified health workers.

Performing the RIF analysis for syphilis, positive data are obtained 2 months after infection. Negative parameters confirm that the subject is healthy. Positive - suggests that the person is infected.

RIT is performed when the microprecipitation reaction is positive. Such a blood test for syphilis helps to deny or confirm the presence of an infection. The test is hypersensitive, it accurately indicates whether the patient is infected or healthy. But the study provides reliable data only 3 months after the penetration of treponemes into the body.

Western blotting method

Ultra-precise tests include immunoblotting. Such a blood test for syphilis is rarely done. It is used when examining newborn children. It is not suitable for express testing. The positive results are received with a delay. The method of microprecipitation gives them much earlier.

IFA and RPGA

To informative ultra-precise research methods include ELISA and RPGA tests. With their help, express diagnostics are carried out. Laboratory assistants do a huge number of such analyzes. Thanks to them, it is possible to establish an accurate diagnosis.

RPHA analysis for syphilis is positive 30 days after the penetration of the pathogen into the body. It is used to diagnose the primary infection when ulcers and rashes appear.

Thanks to him, it is possible to identify neglected, covertly current, as well as congenital forms of pathology. But it is carried out in conjunction with non-treponemal and treponemal tests. Comprehensive diagnostics guarantees the reliability of the results. Triple testing accurately proves the presence or absence of a sexually transmitted infection.

A positive reaction persists over a long period of time. For this reason, research is not used to assess the effectiveness of treatment.

ELISA analysis is positive 21 days after infection. The test sometimes gives erroneous results. They appear with systemic pathologies, impaired metabolic processes. Their effectiveness is questionable in a child born to an infected mother.

Errors obtained with serological methods of research have become the reason for the discovery of progressive diagnostic techniques. Gas chromatography and mass spectrometry do not give false results. The only obstacle to their mass use is their high cost.

Diagnostic algorithm

• When syphilis is in the primary phase (up to 60 days from the moment of infection), the pathogen is looked for against a dark background or fluorescent antibodies are used to detect them.
• If the pathology is in a primary, secondary or latent form, bladder cancer and ELISA are used. An RPHA blood test for syphilis helps to confirm the results.
• With relapses of a secondary infection, the discharge of ulcerations and rashes is analyzed. Pathogens are removed from the samples, studied using microscopy.
• When the disease enters the tertiary phase, 1/3 of patients have negative bladder cancer. At the same time, the results of ELISA and RPHA are positive. However, they do not always indicate the tertiary period, but confirm that the person had an infection earlier. A weakly positive test is evidence of a complete cure, and not the development of a tertiary phase.
• Confirming congenital syphilis, a blood test is taken from the mother and baby. Compare the data of the bladder cancer tests. Consider the fact that the baby's ELISA and RPGA are positive. Confirm the diagnosis using the immunoblotting technique.

Syphilis, like any systemic pathology, affects the entire body. Therefore, examination for him is carried out during pregnancy, before an abortion. Patients are given RMP, ELISA, RPGA.

How to get tested

A venereologist sends patients for analysis. Private laboratories do anonymous testing for syphilis at the request of the client. They do not require a referral from a doctor to take the test.

Research rules:

• In the laboratory, blood is taken in the morning on an empty stomach (eaten after the procedure). Before analysis, only water is allowed.
• 2 days before the examination, it is forbidden to eat fatty foods and drink alcohol.
• Blood is taken from a finger or vein.
• How long does the research take? Usually no more than a day. Deciphering of analyzes for syphilis is obtained from laboratory assistants or the attending physician.
• How long is the test valid? After 3 months, the test results will no longer be valid. They are handed over again.

If the transcript of the analysis shows that the test is positive, it is necessary to visit a venereologist, who will prescribe an additional examination to accurately confirm the diagnosis and select a scheme for the necessary treatment.

Spinal contents testing

The diagnosis of neurosyphilis is made after CSF is examined. This analysis is done by:

• people with a latent form of infection;
• with symptoms of diseases of the nervous system;
• asymptomatic, advanced neurosyphilis;
• recovered patients with positive serological reactions.

A referral to the study of cerebrospinal fluid is given by a doctor. A puncture is taken from the spinal canal into 2 tubes. The puncture is lubricated with iodine, covered with a sterile napkin. After the procedure, the patient adheres to bed rest for 2 days.

In 1 sample, the amount of protein, cells, traces of meningitis is determined. In the second test, antibodies to the causative agent of syphilis are calculated. For this, tests are done: RV, RMP, RIF and RIBT.

Depending on how many violations are identified, there are 4 types of cerebrospinal fluid. Each indicates certain damage to the nervous system. The doctor diagnoses:

• vascular neurosyphilis;
• syphilitic meningitis;
• dorsal tabes and so on.

In addition, the results of the tests are used to judge the patient's recovery.

Interpretation of tests is the responsibility of the physician. Only he is able to draw the correct conclusions, if necessary, appoint an additional examination, make an accurate diagnosis. You should not make an independent diagnosis in case of dangerous systemic pathology. A mistake in diagnosis has serious consequences.

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Syphilis is one of the most dangerous sexually transmitted diseases, the causative agent of which is treponema pallidum. Harmful microorganisms can enter the body after unprotected intercourse and through household use. Today, a blood test for syphilis is basic, it is carried out during a medical examination, and is also required when applying for a job in some organizations.

In addition, the procedure is mandatory for pregnant women. The most effective method for diagnosing this disease is a laboratory study of venous blood. What is the name of the analysis for syphilis, how to prepare for it and how reliable is such a study?

Indications for

Conventionally, all tests for syphilis are called ORS. The acronym stands for selective reaction to syphilis. This term means a diagnostic laboratory study, during which it is possible to detect antibodies to phospholipids, formed due to damage to cells and tissues caused by treponema pallidum.

Testing for syphilis is most often carried out for people with suspected disease, as well as for patients who are assigned a full medical examination. It should be borne in mind that the study involves an additional test for HIV and hepatitis.

And also testing for syphilis is prescribed in the following cases:

• registration of a woman during pregnancy;
• if the patient acts as a donor;
• while staying in places of deprivation of liberty;
• if previous tests have shown the presence of drugs in the patient's blood;
• prolonged increase in the size of regional lymph nodes;
• prolonged fever of unknown etiology;
• previous testing has shown the presence of treponema pale;
• if the person has had sexual contact with infected syphilis;
• the occurrence of dubious symptoms, indicating the development of the disease (the first sign of syphilis is the appearance of rashes in the genital area).

And it is also necessary to submit a biomaterial for research if a person wants to get a job in some institutions:

• military unit;
• hospitals, clinics, laboratories;
• cafes, restaurants, canteens and other places of public catering;
• schools, kindergartens.

Regular testing should be done in patients who have already been diagnosed with this disease. In this case, an analysis is assigned to assess the effectiveness of the selected treatment regimen.

Diagnostic methods

To detect syphilis or confirm its absence, different diagnostic methods and types of tests are used. The most informative and accurate research method is the study of the patient's venous blood. The sampling of biomaterial can be carried out both from a vein and from a finger (depending on the type of laboratory and technique).

In some cases, the detection of pale treponema can be carried out using other samples:

• cerebrospinal fluid (a secret produced in the spinal canal);
• the contents of the lymph nodes;
• ulceration tissue.

Syphilis is diagnosed simultaneously by several methods

Each of the existing tests is informative, has certain advantages and disadvantages. It is only the attending physician who should decide in which way to take the analysis for syphilis, taking into account the individual characteristics of the patient.

Clinical blood test (RV / RW)

The most common way to diagnose syphilis is by conducting it. This immunological procedure is called the Wasserman reaction. Testing belongs to the class of CSC (complement fixation reaction) and was first carried out in 1906.

It is based on the ability of venous blood to coagulate and form a complex when interacting with antigens. Modern methods of RSK in detecting syphilitic infection differ significantly from the classical RW. In fact, these procedures only have the same name.

The diagnosis is made based on whether the sample contains antibodies that indicate the presence of the disease. Despite the fact that testing is the most informative and reliable, the likelihood of a false positive reaction cannot be ruled out.

A false positive response is due to the fact that cardiolipin is initially present in the human body, but usually the immune system does not create antibodies against the native antigen. But medical practice shows that exceptions do happen. Most often this happens if a person has recently suffered a severe viral disease or has encountered the following diseases:

• pneumonia;
• kidney dysfunction;
• hematological diseases.

And also a false positive reaction is often manifested during pregnancy, which is accompanied by a strong weakening of the immune system. If the specialist suspects that the testing has shown a false positive result, the patient is assigned additional extended tests.

Microprecipitation reaction (RMP)

Today, this method of detecting syphilis in the blood is gradually replacing all other methods of diagnosing the disease. The microprecipitation reaction is a study that, in terms of its mechanism, is similar to the Wasserman reaction. But at the same time, the procedure is simpler and more informative - if the sample is infected, white flakes will certainly appear in it.

Another advantage of bladder cancer is that blood is taken for analysis not from a vein, but from a finger. If more than 30 days have passed since the infection, the technique is guaranteed to show a positive result. The risk of receiving false positive information during such testing is minimized and can only manifest itself against the background of such violations:

• aggravated infections;
• recently suffered a heart attack;
• cerebral hemorrhage;
• severe intoxication of the body.

Treponema pallidum immobilization reaction (RIBT)

Another common method of diagnosing syphilis, carried out with the help of venous blood. In order for the RIBT to give the correct result, a few days before the delivery of the biomaterial, it is necessary to exclude the intake of antibacterial drugs.

This is due to the fact that most of the antibiotics, when ingested, block and suppress the activity of pale treponema. A positive response to RYUT appears from about the middle of the second stage of infection and can persist even after the end of treatment.

This is how the causative agent of syphilis looks like under the microscope - pale treponema

RIF and RIT research

Many patients are faced with such a problem that even after the end of syphilis treatment, the analysis shows a positive result. A reliable clinical picture can be identified and evaluated using the hypersensitive tests RIF (immunofluorescence reaction) and RIT (treponema immobilization reaction).

These analyzes are complex and time-consuming and can only be carried out with expensive modern equipment.

RIF analysis for syphilis shows a positive reaction 2 months after infection. If the test showed a negative result, then the patient is healthy. Most often, RIF and RIT analyzes are done with a positive microprecipitation reaction to confirm the reliability of the result.

IFA and RPGA

The most informative and most accurate methods for diagnosing syphilis include ELISA tests (enzyme-linked immunosorbent assay) and RPHA (passive hemagglutination reaction). The main advantage of these studies is that they are prepared within a short period of time.

RPHA gives a positive response within a month after infection and is most often performed simultaneously with non-treponemal and treponemal tests. Usually, with the help of RPHA, the primary form of the disease is diagnosed, accompanied by the appearance of ulcers and rashes. Since RPHA shows a positive reaction for a long time, the technique is rarely used to assess the effectiveness of the prescribed treatment regimen.

An enzyme immunoassay can show the presence of harmful microorganisms as early as 3 weeks after infection. A false positive result is rare and is most often associated with systemic pathologies or dysfunction of metabolic processes.

Preparation for the procedure

You can test for syphilis in any laboratory in Moscow and other large cities. Most often, an appointment for a study is prescribed by a venereologist. If desired, testing can be carried out anonymously, without a referral.

In order for the results of the analysis to be reliable, before the procedure, it is necessary to adhere to the rules of preparation:

• since the sampling of biomaterial is carried out on an empty stomach, it is forbidden to eat before the procedure. The only thing allowed is to drink water;
• 3 days before the analysis, it is recommended to stop consuming fatty foods and alcoholic beverages;
• if the patient took antibiotics, the analysis can be performed only a week after the end of treatment.

Where blood is taken for syphilis depends on the type of procedure prescribed, but in most cases, biomaterial is taken from a vein. The time for decoding the result depends on the type of laboratory, usually laboratory technicians provide results after 1-2 days. And also, in some clinics, an emergency check service is provided, when the results are handed over to hands within a few hours after donating blood.

It should be borne in mind that the analysis for syphilis is valid for 3 months, after this time, testing must be repeated

Decoding the results

Most clinical laboratories will hand out the results form to the patient. The resulting form must be taken to the doctor who ordered the study, who, based on the information received, will assess the overall clinical picture. Can the patient read the test results on their own?

Studying the described information, it is possible to draw only a tentative conclusion, but the final diagnosis is made exclusively by a qualified specialist. During a routine examination or express diagnostics, non-treponemal tests are most often prescribed. The test result is indicated as follows:

• "-" - negative result;
• "+", "++", "1+" "2+" - weakly positive result;
• "+++", "++++", "3+", "4+" - positive test for syphilis.

It should be borne in mind that the result obtained can be both false-positive and false-negative. If the patient does not have traces of syphilis, and the person has not had unprotected intercourse with new partners, the doctor may interpret the false result as true.

Conclusion

Syphilis is a dangerous disease that develops slowly and asymptomatically and leads to serious complications up to the death of the patient. That is why testing for the presence of the disease is recommended from time to time to every person. With the timely detection of the disease, therapy will be more effective and will minimize the risk of developing disastrous consequences.

A disease that goes on without symptoms for a long time is syphilis. Sexually transmitted pathology is caused by the presence of pale treponema. When examining by taking a smear, it is impossible to detect an infection, therefore medicine offers a different way to find syphilis. Blood is considered a suitable research structure. To check, a blood test is taken for syphilis, taking biological material using veins and fingers. How much does it cost, what is the name of the analysis, what preparation is required, as well as other materials are presented in the article.

An infectious pathology that does not have manifestations can lurk inside the body for a long period, gradually destroying and damaging tissues, such as hepatitis. People undergoing mandatory medical examinations should be tested for syphilis. It is important to find out if they have hepatitis and have a blood test for HIV and syphilis. Studies that include serologic testing are performed regardless of obvious or absent symptomatology. Used to detect hepatitis. Indications for testing:

• If showed the use of drugs by the patient;
• When donating donor sperm, blood;
• People in prison;
• In the presence of a test confirming the presence of pale treponema;
• When a patient has symptoms similar to an infectious disease. Manifested by a rash on the genitals;
• When one or more copulations with infected syphilis have been carried out;
• A commission of doctors when applying for work in the following institutions: shops selling food products, cafeterias, restaurants, medical and children's institutions;

• Serology is necessary for girls in position. Girls who have or have had hepatitis know about these tests. A pregnant woman takes the test three times: when she is registered, at 30 weeks, before being sent to the maternity hospital;
• When the baby's mother is sick. An analysis will be done to check for an infectious disease;
• With enlarged regional lymph nodes, long-term fever of an unclear type;
• Check before hospitalizing the patient, excluding hepatitis, syphilis and other diseases;
• When surgery is prescribed.

Delivery process

To obtain an accurate result, they turn to qualified specialists. False positive and false negative results do happen, though not often. For the absence of errors in the reports, a set of rules is observed:

• Like many others, you need to take tests only on an empty stomach;
• Tell your doctor about which medications you are taking, paying particular attention to antibiotics. Indicate recent vaccinations. Mention any type of disease, pregnancy and other things related to the topic of the state of the body;
• It is important for people who smoke to avoid smoking for at least 60 minutes before testing;
• Do not overwork the body, do not consume alcoholic beverages, fatty foods a couple of days before the check.

It is impossible to say exactly how much analysis is done. The dates and times depend on the equipment used. Conducting a general blood test for syphilis, the workload of laboratory staff matters.

Varieties of tests

There are two types:

• Specific, giving a positive result even in the case when the disease has already been cured;
• Nonspecific, manifested in the presence of pathology at the moment.

The appearance of negative data in the results of non-specific analysis is a kind of evidence of a strong organism.

Specific checks

• Immunoblotting;
• Linked immunosorbent assay;
• RIF (Koons method), also called the reaction of immunofluorescence;
• The reaction of immobilization of pale treponema;
• Passive agglutination reaction.

The mechanism of work of specific checks is that when bacteria are exposed to the body, antibodies are produced that attack dangerous microorganisms in response. Immunoglobulins M are formed 14 days after infection. Thanks to them, doctors will learn that the patient has recently become infected. If you do not take any therapeutic methods, the bodies that have appeared remain in the body for many months and even years. The appearance of immunoglobulins G indicates that a month has passed since the infection penetrated. Antibodies can be inside throughout the entire subsequent life span.

Nonspecific checks

• Micro-reaction of precipitation;
• Wasserman reaction.

Conducted during comprehensive medical research for syphilis. If the body is infected, the cells die en masse, which leads to a response. The active production of a special type of proteins by the immune system begins. The test identifies proteins whose concentration can be examined and calculated. After the patient has fully recovered, the results are negative.

Decrypting data

During the decoding of a blood test for syphilis, a method called the Wasserman reaction is used. Express diagnostics, in which the results of a negative nature are not one hundred percent indicator of accuracy. They will be false positive if the patient ate fatty foods, alcoholic beverages a day earlier. When a positive result is made public, a secondary specific test is ordered. According to the intensity of the reaction, medical professionals determine the severity of the pathology.

When evaluating the results, the following notation is used:

• With a weakly positive - "+" or "++";
• For positive - "+++";
• With a sharply positive - "++++";
• For negative - "-".

There is a pathological process if, as a result of the assessment of the obtained antibody titer, the data read from 1: 2 to 1: 800.

Microreaction of precipitation

Doctors increasingly prefer to use this technique over the previous one. Upon receipt of positive data, the probability of the penetration of pale treponema into the body is high.

Results are divided into two types:

• Negative, indicating that the person is healthy, or syphilis is in its early stages;
• Positive, in which the likelihood of illness is very high.

If you pass the test without observing the rules, then the tests obtained often show false positive data.

Immunoassay test

In the general opinion of doctors, this type of analysis can be called the most promising and accurate. The method reveals not only the presence of pathology in the patient, but also indicates if syphilis has been transferred and cured in the past. Even if the patient is cured, tests can show positive results. Antibodies formed in the body will indicate the duration of the illness.

• The presence of immunoglobulins A indicates that a person was infected no more than 14 days ago;
• With immunoglobulins A and M, doctors find out about a recent infection;
• All types of immunoglobulins speak of a time interval of more than a month from the moment Treponema pallidum enters the body;
• With immunoglobulins G, it can be judged that the pathology has been cured, was in the past.

Passive agglutination

Positive test data can indicate the presence of a disease, or a previously transferred form of syphilis. To make an assessment of the resulting antibody titer, examine the data on how long ago the patient was infected.

Immunofluorescence

Negative data indicate the absence of antibodies, and, therefore, the person is not infected. A positive result indicates the presence of syphilis. Determined by the number of pluses or the presence of a minus. There is almost no false positive result.

Immunoblotting method

If the data does not inspire confidence, and the diagnosis is carried out in the baby, then this type of check is used. The service is not offered by all clinics due to the high cost of research.

RIBT

When other types of diagnostics give false positive results, doctors resort to the reaction of immobilization of treponema pallidum. Despite the duration of obtaining results in 12 weeks, this is longer than the previous options, the test gives almost one hundred percent information, is susceptible to infection.

Test locations

Medical facilities provide the service. We are talking about diagnostic centers, private clinics, polyclinics, dermatovenerologic dispensaries. Tests are taken free of charge in all government agencies.

For accurate data, blood is donated on an empty stomach using the ulnar vein. With positive results, one should not despair, modern medicine is successfully combating pathology. If you have the slightest suspicion of infection, you should immediately consult a doctor in order to start therapy without dangerous consequences.