Increased and decreased creatinine in the blood. What is creatinine in the blood

Why get tested?

If the patient has symptoms of kidney disease, all three tests are indicated.

These symptoms usually include:

• Constant feeling of tiredness;
• Insomnia;
• Loss of appetite;
• swelling of the face;
• Pain in the lower back (near the kidneys);
• Frequent urge to urinate;
• High blood pressure;
• Nausea and vomiting.

Kidney problems can be triggered by various diseases:

• Glomerulonephritis - inflammation of the glomeruli of the kidneys;
• Pyelonephritis;
• Inflammation of the prostate (in men);
• Stones in the kidneys;
• cystitis (in women);
• Heart failure, diabetes(types 1 or 2), dehydration;
• The death of kidney cells due to the use of narcotic drugs.

What is creatinine in blood tests and why its indicator is needed is hardly known to the average visitor to the clinic. He (or she) thinks something like this: “Well, they wrote me creatinine here. And even the norm of creatinine is shown. And what should I do with these indicators? Of course, the sheet with the results of the blood test goes to the doctor, and he writes a lot of incomprehensible things in the book in illegible handwriting.

Naturally, the desire of many recipients of doctor's instructions to at least understand something for themselves. We understand.

Creatinine is important chemical compound in the human body, formed as a result of the breakdown of protein molecules. This substance is an integral part of the residual nitrogen.

At the beginning of the transformation chain is creatine. This component carries out a long way through the body, starting in the renal parenchyma. Methylation occurs in the liver. After that, the substance is sent to the muscles, where creatine phosphate is created from creatine. The resulting component goes to the myofibrils, where it breaks down into creatinine and phosphate, giving the muscles energy to contract.

After its use, the remains follow into the blood. In the liver, creatinine is not affected, because due to its structure, and without any problems, it is excreted in the urine. This energy turnover occurs constantly, because of this, the amount of substance in the circulatory system remains the same, provided normal state organism.

Energy turnover

The process of converting creatine to creatinine using the energy obtained, described above, is quite complex. However, we use the result unconsciously. Who in life thinks that I need to raise my hand, and for this, such biochemical processes? That's right - no one. But they pass because man is a “biochemical machine”.

Everything happens literally instantly under the control of commands from the brain. Suppose you decide to pour yourself a cup of tea from a teapot. How does this happen? You have to raise your hand, take the teapot, bring it to the cup and pour it. What is causing all these movements? Due to the energy that creatinine gives (releases) to the muscles.

We do not delve into a complex process, but it is quite clear that in order to perform actions, our muscles must release the necessary amount of creatinine (that is, energy). This amount is determined by our body independently, depending on many factors. Including muscle training.

It is no coincidence that the so-called “pumps” in the gym often use special supplements called “Creatine”. Allegedly, these supplements add raw material to convert it into creatinine, which seems to allow you to pump up huge muscles. In fact, these supplements do not work (personally tested by the author of this article) as they would like.

So, using the allocated energy, the body is not able to process the excess in any way and the excess creatinine must be removed from the body.

Creatinine level

This indicator is completely dependent on gender and age, as well as on the performance of the kidneys, accumulated muscle mass and consumption preferences. food products. In the human circulatory system, there are 2 types of biologically active substances: endogenous - which is formed directly in the body itself - and exogenous (coming from outside).

Therefore, if the level of creatinine in the blood is slightly higher than normal, and the person who passed the tests has an athletic build and does not belong to people who eat only plant food then there is no cause for concern.

When examining a patient, his age category should also be taken into account. If these are elderly people, then the creatinine level decreases, therefore, the results of the analysis simply state age-related changes organism.

Please note that the creatinine norm for different sexes will be different. This can be explained by the fact that the strong half is endowed with more muscle mass that needs to be set in motion (which means more energy should be released) than the female (as a rule, roundness appears due to the deposition of fat, which does not produce contraction and does not need additional energy ).

In childhood and adolescence, the content of creatinine varies according to the age category.

Norm of creatinine in mg/l:

• newborn child up to 1 year from 3.0 to 11.0;
• from 1 year to 7 years from 2.0 to 5.0;
• from 7 to 14 years from 3.0 to 8.0;
• from 15 to 16 years from 5.0 to 11.0;
• men from 8.4 to 13.6;
• women from 6.6 to 11.7.

When conducting an analysis, other units of measurement can also be used - this is micromoles per liter (µmol / l). In this case, the normal range for women will be from 44.0 to 97.0 µmol/l, and for men from 44.0 to 115.0 µmol/l. This indicator is most often determined in the urine. At healthy person up to 2 g of creatinine per day is excreted with urine (the norm is from 1 to 2 g).

The level of creatinine differs between men and women also in that the female half of the metabolic processes in the body proceed more slowly, the diet is also different, it has an effect hormonal background especially during pregnancy.

In children of different sexes up to 14 years, the content of the creatinine level is the same.

What is dangerous elevated creatinine

A small deviation of creatinine from the norm can not be considered a problem, since the person is in a constant energy metabolism and at the next moment in time the excess energy can be used. But why is the condition dangerous when the creatinine norm is seriously exceeded?

Recall that the body cannot do anything with creatinine, except to remove it. For some reason, problems with withdrawal lead to the accumulation of creatinine in the blood. Accumulated in the blood beyond measure, creatinine begins to exert toxic effect on body systems, gradually increasing their poisoning.

It happens that too high level leads to the need to carry out hemodialysis (blood purification), so as not to lead the body to destruction.

Creatinine test

The main task for creatinine, which a doctor can recommend, is to identify a violation of the urinary tract.
systems (mostly kidneys). The fact is that with good kidney function, there are no problems with the withdrawal and the creatinine norm is observed. But the excess of the norm may indicate the presence of any hidden diseases, kidney diseases, namely renal failure.

A blood test for creatinine is required if:

• You are a kidney donor;
• You suspect kidney failure urolithiasis or diseases of the muscular system;
• To determine the exact dosage of a medicinal product with toxic effect on the body.

To determine the content of creatinine in the circulatory system, you need to donate blood for a biochemical study. To obtain a reliable result, it is necessary to stop drinking alcohol, coffee and strong tea for a day, and also not to abuse protein foods, such as meat. Refrain from increased physical activity.

The analysis is taken in the morning on an empty stomach from a vein. Before passing the analysis, it is necessary to sit for some time in a calm and relaxed state. The analysis study is started immediately. The result will be ready on the same day.

Reberg's test

Otherwise, this test is called "creatinine clearance" and is a more thorough method for determining its level. It determines the presence of renal failure and the effectiveness of blood flow through the renal glomeruli. For its implementation, two biological environments of the body are surrendered - this is urine and blood.

A blood test is performed in the morning on an empty stomach.

Urine is collected within 24 hours, except for a portion after a night's sleep.

All collected samples are poured into a 5-liter container and stored in a dark, cool place. After the last urine sample, we pour part of the urine into a separate container (30 ml is enough) and submit it to the laboratory for analysis.

For the reliability of the results, the following conditions must be met:

• It is necessary to refuse the use of drugs or inform the doctor about their use in advance;
• Observe hygiene rules for the genitals;
• A contraindication to taking an analysis in the female half is monthly uterine bleeding.

When submitting to the laboratory in a hospital, you must indicate your weight and height.
The result is the rate of clearance of body fluid from creatinine and is indicated in milliliters per minute.

Reberg's test is prescribed in controversial cases, when the usual analysis is not enough. But really modern medicine constantly improving and finding new diagnostic methods.

For reference. Despite the fact that the analysis of the level of creatinine has been used for a long time and quite widely, in Lately The medical community is inclined to believe that a more accurate marker for detecting kidney disease is cystatin C protein.

A large long-term study has practically proved that cystatin C is able to predict the development of chronic renal failure in advance and cardiovascular disease in older people. A very important research finding!

Causes of deviation of creatinine from the norm

The main reason for the increase in the level can be attributed to its increased production or deterioration in the process of removing this substance from the body. However, elevated creatinine can also occur with the following pathologies:

• Liver disease of a toxic, cirrhotic and inflammatory nature;
• tissue necrosis and internal organs organism;
• kidney failure;
• A disease associated with excessive production of thyroid hormones;
• Injury to the muscle and skeletal systems, as well as burns of a large area;
• Complication of diabetes mellitus due to vascular damage in the kidneys;
• Excess content of the adrenal cortex;
• A disease characterized by weakness of the muscular system;
• Diseases of the pulmonary system;
• Prolonged feverish conditions;
• The period of gestation;
• Exposure to drugs that have a toxic effect on the kidneys;
• Increased load on the muscular apparatus.

To reduce the content of this component lead to:

• Starvation;
• The period of gestation;
• Long-term treatment with corticosteroids.

It should be noted that during pregnancy and during fasting, both a decrease and an increase in the level of creatinine in the blood can occur.

Symptoms of high creatinine

An increase in the level may be accompanied by the following symptoms:

• weakness, drowsiness, loss of strength;
• nausea;
• headache;
• hard breath.

Accordingly, a high level of creatinine in the blood is an indirect sign of kidney failure, destruction and inflammation in the muscular system, or the presence of infectious diseases accompanied by kidney damage.

How to reduce blood creatinine

Attention! It is highly undesirable to engage in lowering creatinine levels on your own. Need to consult with a specialist proper treatment or dietary restrictions. If a high rate is a consequence of any disease, then it is necessary to deal with the root cause of the development of this pathology.

If the reason lies in malnutrition, then it is recommended to abandon the following products:

• Fatty varieties of fish and meat;
• Smoked and spicy food;
• Milk and lactic acid products;
• Cheeses;
• Strong coffee and tea;
• Salt and sugar.

In general, you should limit yourself to eating protein-rich and salty foods, but it is better to switch to foods containing antioxidants (cabbage, beans, pistachios, Walnut, oranges, strawberries, eggplants and others). It is also recommended to drink at least 1 liter of pure water.

To lower the creatinine content, a specialist may prescribe medications, for example, Lespeflan, Ketosteril, Lespenefril and others.

With a very high level of creatinine, hospitalization in a specialized hospital department is indicated. In extreme cases, artificial cleansing is carried out circulatory system using an artificial kidney.

Attention. Elevated creatinine refers to the first "bell" about the presence of any serious pathologies, so it is imperative to find and eliminate the cause.

• Creatinine is a nitrogenous compound, which is, in fact, a waste (end product) of metabolism in muscle tissues.
• Creatinine is made from creatine, which has great importance for energy production in skeletal muscle.
• Approximately 2% of creatine is converted to creatinine in the human body every day.
• From muscle tissue through the blood, creatinine enters the kidneys, where it is filtered and excreted from the body in the urine.
• Since the muscle mass of each person remains relatively constant from day to day, the daily production of creatinine in the body does not change much.

Why is it necessary to control the level of creatinine in the blood?

Thanks to the kidneys, the level of creatinine in the blood is maintained in a certain range, which is considered normal. It has been established that the analysis of the actual level of creatinine in the blood is a fairly reliable indicator characterizing the function of the kidneys. If the level of creatinine is elevated, this indicates existing impaired renal function up to renal failure. That is why the analysis of creatinine is provided in the minimum profile of a biochemical blood test.

What level of creatinine in the blood is considered normal?

Young or middle-aged muscular people may have blood creatinine levels higher than the average for the general population.

In starving people, people with significant loss of muscle mass, vegetarians, the content of creatinine in the blood will be below the norm for their age. A decrease in the rate is possible in the first and second trimesters of pregnancy.

After the removal of one of the kidneys, an increase in blood creatinine to 1.8-1.9 mg / dl can be considered the norm.

When does blood creatinine rise?

Creatinine levels greater than 2.0 mg/dL (177 µmol/L) in children and 5.0 mg/dL (442 µmol/L) in adults may indicate severe renal impairment.

Causes of increased endogenous creatinine:

• acute and chronic kidney failure;
• damage to muscle tissue as a result of injury, surgical interventions, inflammatory processes, including infectious diseases;
• radiation sickness;
• hormonal disorders: acromegaly and gigantism,;
• taking nephrotoxic drugs: nitrofurazone, ibuprofen, sulfonamides, aminoglycosides, tetracyclines, cephalosporins, salicylates, barbiturates, cimetidine, etc.
• high protein diet (eating a lot of meat);
• dehydration.

Larger increases in this indicator (> 13.5 mg / dl or > 1200 μmol / l) may be an indication for hemodialysis and kidney transplantation, while taking into account other indicators: creatinine clearance less than 10 ml / min, and urea above 35 mmol / l.

What symptoms can be associated with high creatinine levels?

Symptoms of kidney dysfunction (renal failure) vary widely. As a rule, the symptoms of kidney failure do not directly correlate with the level of creatinine in the blood. Some patients become aware of high creatinine and serious problems with the kidneys quite by accident, while having almost no symptoms. In other cases, the following symptoms may indicate kidney failure:

• increased fatigue, fatigue;
• swelling, especially morning swelling of the face and upper body;
• dyspnea;
• confusion;
• non-specific symptoms: nausea, vomiting, dry skin, etc.

How to lower blood creatinine?

It should be remembered that a high level of creatinine according to the results of a biochemical blood test is important information for the attending physician, however, one or another diagnosis cannot be made only on the basis of such an analysis. Moreover, it is impossible to engage in self-diagnosis and start treatment on your own, without having the necessary knowledge.

If the cause of high creatinine is a disease, then treatment should be aimed directly at eliminating the pathological process and restoring kidney function. After the normalization of the activity of the urinary system or after the restoration of the health of the muscle tissue, the creatinine levels return to normal values.

If creatinine has increased due to medication, then a decrease in its level in the blood will occur some time after the end of the course of treatment.

You can reduce creatinine in the blood by normalizing your diet, namely by reducing the amount of meat dishes in it.

What is endogenous creatinine clearance?

A more accurate assessment of kidney function can be made by calculating the rate of excretion of creatinine from the body. This indicator is called endogenous creatinine clearance and characterizes the glomerular filtration rate. Endogenous creatinine clearance can be calculated in two ways:

1. Creatinine clearance (ClCr, ml/min) is calculated using a formula using the measured serum creatinine level (CrCl, mg/dL). The age of the patient in years is subtracted from 140, and the resulting value is multiplied by his weight in kilograms. The result of the calculation is divided by the level of serum creatinine, multiplied by 72. For women, the resulting value is multiplied by a factor of 0.85. Briefly, the formula looks like this:

• Men: ClKr = ((140 - age) × weight) / (72 × CrPl);
• Women: ClKr \u003d ((140 - age) × weight) / (72 × CrPl) × 0.85.

1. Creatinine clearance can also be calculated by measuring the level of creatinine in a daily urine sample and its level in the blood (Rehberg-Tareev test). The resulting values ​​are compared. For 6 hours before the collection of urine and blood sampling, the patient should not eat meat, poultry, fish, and tea. During the day, while urine is being collected, the patient should not be subjected to heavy physical exertion. Urine is collected in a container with a volume of about three liters. The container with the collected urine is stored in a cool place, no preservatives are added to it. If necessary, the patient's weight and height are noted. At the end of the day, the volume of collected urine is estimated, about 20 ml of urine is poured into a special container, which is sent to the laboratory to determine the level of creatinine. The rest of the urine is destroyed. At any time of the day, while urine is taken, a blood sample is taken from a vein, followed by the determination of creatinine.

Normal values ​​of endogenous creatinine clearance

If creatinine clearance is below normal

The use of thiazides, diazoxide, triamterene, nephrotoxic drugs, the use of opioid drugs and cannabis can reduce the measured values ​​of creatinine clearance.

Low creatinine clearance may indicate the presence of the following diseases:

• Kidney disease:, nephrotic syndrome, congenital kidney disease, interstitial nephritis, acute dysfunction tubules, papillary necrosis,
• General diseases: amyloidosis, malaria, multiple myeloma, cystinosis, Wilson-Konovalov's disease, vitamin D-resistant rickets.
• Conditions accompanied by a decrease in blood supply to the kidneys: blood loss, dehydration, heart failure.
• In obstetrics: , eclampsia.

Degree of decline:

If creatinine clearance is above normal

To increase the clearance of endogenous creatinine can: protein diet, excessive exercise, drugs based on amino acids, furosemide, carbenoxlone, levodopa, methylprednisolone.

High clearance rates can be hypertension, diabetes, burns, pregnancy.

What is the significance of urea in the blood?

Urea is another end product of protein metabolism. Formed in the liver from amino acids and excreted by the kidneys. Urea in the blood is another indicator of the excretory function of the kidneys.

Normal blood urea levels:

Elevated levels of urea may indicate a violation of the excretory function of the kidneys or excessive synthesis of urea with increased protein catabolism.

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A standard biochemical blood test can detect a change in the concentration of creatinine in serum or plasma. These data are used when necessary to diagnose kidney function. Sometimes the indicators go beyond the norm, but why does creatinine in the blood rise? The reasons for this deviation are discussed below.

Creatinine is elevated, what does it mean

To understand what elevated creatinine in the blood means, you need to figure out what kind of element it is, how it is formed. This substance is the end product in the metabolic breakdown of creatine phosphate, which is an organic compound involved in the process of obtaining energy during muscle contraction. From a chemical point of view, it forms a substance from creatine when the phosphate group is cleaved from creatine phosphate.

In healthy women and men, this element is constantly generated. There is a specific value of the norm, which depends on age, muscle volume. For the same reason, the figure is usually higher in men than in women, because there is more muscle mass. The amount of the element will increase with age, so the rate in children is always lower than in adults. A decrease in the indicator is noted during pregnancy due to an increase in the volume of blood circulating in the body.

The element is removed from the body along with urine, it is a “non-threshold” substance (it is completely filtered out in the renal glomeruli in the absence of pathologies). The element is not affected suction, therefore, it leaves the human body completely. Detection of creatinine in the analysis of plasma indicates a violation of the kidneys (renal failure). An important indicator in the diagnosis is the Reberg test:

1. The element is measured in plasma.
2. Then its amount in the urine is measured.
3. The indicators are compared and the clearance of the substance is calculated.

Due to muscle atrophy in the body of an elderly person, the level of the element in question is significantly reduced, therefore, when analyzing kidney function, it is impossible to rely only on the study of the amount of this substance. Kidney function may be reduced significantly more than a blood test for the amount of this substance in serum or plasma shows. In this case, this analysis is not considered indicative.

Norm of creatinine

To understand that creatinine is elevated, you need to know it normal level. Doctors should take into account that the kidneys have reserve latent capabilities, so normal maintenance is not a reason for an unambiguous conclusion about the absence of diseases. In some cases, even a significant damage to the kidney tissue does not affect the level of the element. For diagnosis, data on the amount of urea in the blood are important, which indicates the state of the kidneys directly.

Blood sampling should be done in the morning before meals. The unit used to measure the level of a substance is mmol/l (millimoles per liter) or µmol/l (micromoles per liter). The following indicators are considered normal for a person:

Increased creatinine in the blood for physiological reasons

There are two factors that can explain why blood creatinine is elevated - pathological and physiological. The first is caused by diseases that affect the functioning of the kidneys, the second is the natural reaction of the body to external and internal changes that are not dangerous to health. All these factors during the examination must be announced to the doctor. Creatinine in the blood is increased - physiological reasons:

1. Age. In older people, the level of this substance may fluctuate slightly, which is the norm. During adolescence in children (the time of active growth), there is an increase in the amount of the element in question. After that, the level should return to normal.
2. Floor. Compared to men, women should have a lower figure (assuming the same age), which is explained by a smaller amount of muscle mass.
3. Pregnancy, hormonal background (in women in particular). These two factors can increase protein metabolism, which will lead to an increase in the substance.
4. Physical exercise. For athletes, people who are engaged in active physical labor at work, the norm of the substance should be higher.
5. Muscle mass, their volume. This factor must be taken into account when biochemical analysis serum of athletes who are engaged in weightlifting, bodybuilding. The more muscles, the higher the rate, which is not considered a symptom of impaired kidney function.
6. Nutrition. Many athletes follow a protein diet to stimulate muscle growth. A large number of protein leads to an increase in creatinine in the blood. The same effect is observed with prolonged fasting, which also provokes the destruction of muscle fibers for energy generation.
7. Dietary supplements that contain the amino acid creatine also cause the element to be elevated in plasma.

High blood creatinine due to pathological causes

The second group of reasons why creatinine rises refers to pathological abnormalities. This phenomenon is called hypercreatininemia. It can act additional symptom other diseases and be the main criterion for diagnosis. The degree of growth of the substance may indicate the causes of the development of the pathological condition. There are two stages of hypercreatininemia.

Moderate, insignificant - reasons:

• kidney pathology, organ failure of 1, 2 degrees;
• the cause is inflammatory, toxic or cirrhotic liver damage;
• increased rate observed due to massive necrosis of tissues, gangrene of internal organs, limbs;
• growth occurs due to extensive burns, damage to bones, muscle tissue;
• thyrotoxicosis - hyperfunction of the thyroid gland;
• an increased rate provokes diabetic nephropathy, the cause of which was diabetes mellitus;
• myasthenia gravis;
• adrenal hyperfunction;
• the cause of the increased value may be a toxic effect on the body from harmful substances, severe pathologies, for example, intestinal obstruction, infection, peritonitis;
• medications, which have a nephrotoxic effect, are able to influence the body, which provokes an increased level of the element;
• toxicosis, which complicates the course of pregnancy, can act as a cause;
• excessive loss of fluid or its insufficient intake into the body leads to an increased value;
• massive damage to connective tissue due to autoimmune disease(lupus erythematosus, rheumatoid arthritis);
• decompensated heart failure, which has a pronounced stagnation in big circle blood circulation, causes an increased content of the element.