Rehberg urine analysis - diagnostic method, which allows you to evaluate the functional activity of the kidneys, their ability to filter blood and secrete toxins and wastes. Laboratory research is based on calculation average speed glomerular filtration. The test is indicated for patients with urinary disorders, as well as for suspected kidney disease. Paired organs constantly cleanse the blood of metabolic products, so disruption of their work negatively affects all human life systems.
The Rehberg test (or endogenous creatinine clearance) is a hemoral test that is often used to differential diagnosis pathologies of the urinary system. Creatinine takes part in energy processes that occur as a result of muscle contraction. Creatine phosphate loses its phosphate group, after which, during chemical reaction Creatine is converted into creatinine. At in good condition health, this compound is constantly present in the body, and its quantitative content in the bloodstream is a constant value.
The concentration of creatinine depends on the total mass of human muscle tissue. In representatives of the stronger sex, the level of the substance is significantly higher than in women. Athletes with developed muscles or people engaged in heavy physical labor have large amounts of creatinine in their bodies.
The principle of urine analysis according to Rehberg is based on the following properties:
A decrease in the concentration of creatinine in urine leads to an increase in its amount in the bloodstream.
This directly indicates renal dysfunction and the possible presence of an inflammatory process. The paired organs have, to one degree or another, lost the ability to fully filter blood.
Using the Rehberg test you can analyze:
Patients with diabetes are advised to regularly provide urine for this laboratory test. With its help, endocrinologists monitor the effectiveness of treatment and the development of possible complications.
Doctors prescribe Rehberg urine tests to patients for diseases that occur against the background of partial loss of glomerular filtration capacity, renal failure, excessive deposition of nitrogenous metabolic products.
It is necessary to collect urine for examination if the development of the following pathologies is suspected:
The rate of decline in filtration depends on the degree of impairment of glomerular filtration. Diseases of the urinary system caused by pathogenic microorganisms gradually reduce the ability of the kidneys to cleanse the blood. And with diabetes, the pathological process progresses rapidly.
The Rehberg test is performed to determine the cause of pain in the lumbar region, swelling in the face and legs, and problems with bowel movements. bladder. You should submit your urine for examination if there is a change in the color and smell of the urine, the appearance of fresh blood or dark spots in it. blood clots, pus, mucus. Laboratory analysis is prescribed in the form of an initial differential diagnosis of malignant and benign tumors.
A urine test is indicated for patients in whom doctors suspect acute or chronic renal failure, especially if the following symptoms of renal pathology are present:
During pregnancy, the growing uterus can put pressure on the kidney, urinary tract, and bladder. If, during a general urine test in a pregnant woman, unsatisfactory results were obtained, then a urine analysis according to Rehberg is prescribed to confirm the recorded values. Early detection pathological process will help avoid the appearance of symptoms of renal failure during pregnancy: swelling, late gestosis, arterial hypertension and temperature rise.
In the third trimester of pregnancy, a urine test according to Rehberg is indicated.
To carry out the Rehberg test, 24-hour urine will be required, during which the patient must follow certain rules. 2-3 days before submitting a biological sample to the laboratory, you need to exclude:
You should not drink more water than usual - this will distort the results of the study. Patients with acute or chronic diseases You need to inform your doctor about the medications they are taking. Some medicines will influence the obtained values. These include:
The doctor will help you correctly adjust the dosage or make a temporary replacement of medications. During menstruation, a Rehberg urine test is performed only if absolutely necessary, since at this time a woman experiences hormonal changes.
Before collecting urine, you should place it in a clean, dry container with a volume of 2-3 liters. You also need to purchase a sealed container at the pharmacy that can hold 100 ml of liquid. The biological sample is collected in the morning at 6-7 o’clock exactly one day before visiting the laboratory. Before each urination, the genitals are washed warm water. When carrying out hygiene procedures, you cannot use soap, gel or foam due to the additives contained in these products.
The first emptying of the bladder should be done in the toilet - it is too concentrated. Subsequent urinations are performed in a prepared container, which should be stored in a cool place, protected from light. A day later, 100 ml of collected urine is poured into a container and hermetically sealed. The last emptying of the bladder occurs no later than 2 hours before the delivery of the biological sample.
Simultaneously with the study of 24-hour urine, a patient’s blood is analyzed to determine creatinine clearance. To confirm the initial diagnosis, the doctor takes into account percentage between the obtained values. The glomerular filtration rate is calculated using the following formula: the concentration ratio of creatinine in urine multiplied by plasma creatinine parameters multiplied by the amount of creatinine in urine times the collection time displayed in minutes. When making calculations, the patient's height and weight are taken into account. Therefore, the normal values vary over a fairly wide range.
Deviations from the norm in the Rehberg test values indicate a decrease in the functional activity of the kidneys for as yet unknown reasons. Only a highly specialized doctor is able to decipher the results of the examination, comparing them with the manifestations of symptoms. The following parameters of creatinine clearance are taken as the norm:
Minor deviations from the norm do not serve as a signal for further diagnosis. Even serious differences between the norm and the obtained parameters do not always indicate the development of any pathological process in the body. The causes of deviations are often unbalanced nutrition, consumption of salty and spice-rich foods, increased motor activity. Poor Rehberg test results are often diagnosed in women in the third trimester of pregnancy and in people with extensive burns.
It is convenient to collect daily urine for the Rehberg test in special containers
Elevated values indicate the possible development of:
Low rates indicate the inability of the renal glomeruli to fully filter the blood from toxic compounds, toxins and metabolic products. After studying the results, doctors diagnose the following diseases:
If the glomerular filtration rate decreases, it is necessary to evaluate liver function and cardiovascular system. Diabetes insipidus may also be accompanied by renal dysfunction.
The results of a Rehberg urine test can only confirm the suspicions of a doctor (urologist, nephrologist, gynecologist, endocrinologist), but its values are not intended to make a diagnosis. Based on the obtained abnormal parameters, the doctor prescribes instrumental studies. And only after studying their results, clinical picture and diseases in the patient’s history, the doctor makes a diagnosis and begins treatment.
Urine examination according to Rehberg is a type of hemorenal test. This procedure helps evaluate the performance of the kidneys when performing cleansing actions. Rehberg urine analysis calculates the rate of filtration and purification of the blood from harmful substances.
The standard Rehberg examination procedure is carried out to diagnose the development of pathology. Should be carried out this procedure people with renal failure or those who have complications of parenchymal renal function.
For those who have kidney failure, it is important to regularly conduct such examinations in order to correctly diagnose pathologies:
Tubular reabsorption of fluid from the body is noticeably reduced in people with diabetes insipidus or with a wrinkled kidney from leakage, pyelonephritis and others.
In addition, glomerular filtration decreases with the following painful values: inflammation, kidney diseases with diabetes and hypertension, glomerulosclerosis.
When the levels drop to a minimum, this is a sign of severe renal failure or final stage of renal failure.
Any analysis requires preparatory actions for quality results and avoiding inaccuracies. Urine should be collected in the morning at 6 o'clock and finished at the same time. It is important to take it first water treatments. You can buy a jar at the pharmacy or boil any container to eliminate bacteria. The collected urine should be kept in a cool place in an amount of 200 ml for research.
Before collecting urine, you should not drink alcoholic beverages that contain caffeine. This may have negative influence on the test result. At regular use medications, you need to consult a doctor and find out whether the drugs can affect blood and urine counts.
Some drugs are used daily, so a warning must be given and he will take into account the expected bias in the urine test results. Before collection, in the evening, it is not recommended to eat meat products or drink at night. The last intake of food and liquid should be 7 hours before the first urination. After completing the test, the person’s blood must be taken for testing. This is necessary to clarify the % relationship between creatinine in urine and blood.
Analysis of the results of the study does not apply to the method of diagnosing the disease or the course of the pathology. The urine test procedure will help confirm or prove the falsehood of the assumption. Creatinine clearance confirms the presence or absence of differences from normal indicators functioning of the kidneys and endocrine system.
After taking actions aimed at implementing this study urine, the results will be an important basis and sign for obtaining the correct statements of the specialist.
To make a correct diagnosis, medical worker Only the results of a urine test will be required. The doctor will pay attention to all factors, including medical history, symptoms and other aspects. The table shows the indicators that should be in permissible limit at healthy person.
Diminished designations cause a decrease in the level of the patient’s kidneys when taking a urine test for the Rehberg test. Large indicators during a urine test according to Rehberg can inform about the beginning of the formation of diabetes mellitus in a person or pathologies associated with a serious increase in blood pressure or confirm the presence of generalized edema.
Using a urine test according to Rehberg, the removal of final metabolic products from the body is checked, the ability of the kidneys to perform a key function - to cleanse the blood of metabolic products. At initial stage formation of urine and reabsorption of fluid from the body, the substance creatinine is removed - important indicator, informing about the performance of human kidneys.
At normal values creatinine must be excreted from the body in large volumes, because of this, some of the substances are indicators of kidney function. When the level decreases and increases in the blood, malfunctions may occur in the organs of the urinary system.
The Rehberg urine test procedure is a type of hemorenal test. Assists doctors in analyzing the activity of the kidneys when they cleanse the body of metabolic products - urine analysis. The Rehberg test effectively calculates the rate of filtering and elimination from plasma harmful elements kidneys.
The Rehberg test refers to studies of the functioning of the kidneys, namely their ability to filter blood plasma with dissolved substances in it. harmful substances(“slags”) and absorb from the resulting primary urine excess liquid. The Rehberg test helps evaluate the filtration and concentration functions of the kidneys. They are broken when various diseases– , nephropathies, . Our article describes when and how to take the Rehberg test and what its results mean.
It must be said that the Rehberg test, developed in 1926, was not without its drawbacks, since it required intravenous administration of creatinine. In the 1930s, the Soviet doctor Tareev found that the level of this substance in the blood plasma is practically independent of external conditions and suggested using “endogenous” creatinine, which naturally produced by the breakdown of protein molecules.
The Rehberg test is based on determining the difference in creatinine levels in the blood and urine. Creatinine is a substance that arises from the breakdown of protein compounds and is excreted only by the kidneys. In the glomeruli, creatinine comes from blood capillaries into Bowman's capsule and is part of the primary urine. Moreover, its content in plasma and primary urine is normally the same.
Primary urine from the glomeruli enters the renal tubules, where intensive absorption of certain salts and water occurs. Creatinine is not reabsorbed. The volume of urine decreases, and the concentration of creatinine in it increases.
The test primarily determines the glomerular filtration rate (GFR), that is, the activity of the kidney tissue. It is calculated as follows:
GFR = urine output per minute (ml/min) * urine creatinine (µmol/l) * 1000 / blood plasma creatinine (µmol/l).
GFR can also be referred to as creatinine clearance - that is, the volume of plasma completely cleared of creatinine by the kidneys in 1 minute.
Depending on this indicator, the second one is calculated - tubular reabsorption (TR), that is, the ability of the renal tubules to absorb water from primary urine.
CR = (GFR - diuresis during determination) / GFR * 100
Depending on the time of urine collection, the Rehberg test can be taken within an hour, two or even days. The time for taking the test must be checked with your doctor, since kidney function indicators may differ during the day and at night for some diseases.
First, blood is taken from a vein on an empty stomach and its creatinine level is determined. Then the patient lies down on the couch and collects urine for 1 hour in 1 container, and for the next hour in another. Next, the creatinine content in this urine is determined, as well as the amount of urine excreted in 1 minute.
Sometimes the test is carried out with a water load, when before the analysis the patient is given 400 ml of water to drink, then he urinates, and this urine is not used for calculation. After half an hour, his blood is taken for analysis, and after an hour he can urinate to determine the concentration of creatinine in plasma and urine.
Then the doctor uses the given formulas to determine the values of GFR and CR and compares them with the norm.
The test must be taken for patients with the following complaints:
Additionally, it is necessary to pass tests according to Zimnitsky and Nechiporenko, urine culture on a nutrient medium, etc. Additional assistance in diagnosis will be provided by ultrasound, CT or MRI of the kidneys, angiography, excretory urography and other research methods.
In a number clinical situations The Rehberg test is carried out with a water load. The Rehberg test is deciphered by the doctor who referred for the analysis - therapist, nephrologist, urologist.
These are average values, however, there are more accurate tables of creatinine clearance (µmol/min) depending on the age and gender of the person.
| Age, years | Men | Women |
| Less than 1 | 65 … 100 | 65 … 100 |
| Up to 30 | 88 … 146 | 81 … 134 |
| From 31 to 40 | 82 … 140 | 75 … 128 |
| From 41 to 50 | 75 … 133 | 69 … 122 |
| From 51 to 60 | 68 … 126 | 64 … 116 |
| From 61 to 70 | 61 … 120 | 58 … 110 |
| Over 70 | 55 … 113 | 52 … 105 |
Glomerular filtration increases:
Glomerular filtration decreases in the following conditions:
If creatinine clearance drops below 30-50 ml/min, this means that its unresolved excess begins to accumulate in the blood and poison the body. Uremia occurs. If GFR is less than 15 ml/min, an urgent procedure is necessary to save the patient’s life.
Tubular reabsorption, that is, a violation of the reabsorption of water from primary urine leads to an increase in diuresis and is observed at more late stages renal failure. Reasons for decreased tubular reabsorption.
Blood passes through the kidneys hundreds of times every day. Nephrons are responsible for its purification - small filters, inside of which there are bundles of capillaries - glomeruli. This process is called glomerular filtration. The quality of glomerular function can be assessed by studying the rate of blood passage through the nephrons (glomerular filtration rate).
After filtering the blood, some compounds necessary for the body, return back to the bloodstream. However, there is a substance that, after filtration, must be completely excreted in the urine. This is creatinine - a product formed as a result of the breakdown muscle tissue and is “garbage” for the body. An increase in its concentration in the blood indicates a deterioration in glomerular filtration. During the Rehberg test, creatinine clearance is assessed (an indicator of the rate at which it is cleared from the blood).
The study appeared in 1926 thanks to the Danish physiologist Paul Rehberg. He proposed studying the rate of renal blood flow by assessing the excretion of exogenous (introduced artificially, through a vein) creatinine from the body. But this method turned out to be difficult to implement.
However, Rehberg's proposal was not useless - thanks to him, scientists were able to establish that normally the level of creatinine in the blood of a healthy person hardly changes during the day. And in 1936, the Soviet scientist Evgeniy Tareev improved Rehberg’s method by beginning to evaluate the clearance of endogenous rather than exogenous creatinine. Therefore, the study is sometimes also called the Reberg-Tareev test.
In the presence of pathologies, it is the filtration capacity of the kidneys that suffers first.
The value of the Rehberg test is that it allows you to identify diseases in the early stages.
The study can be carried out at the request of the patient in for preventive purposes(this is especially true after 40 years).
Important. In some cases, the Rehberg test is prescribed during pregnancy - during this period, a woman’s kidneys experience enormous stress, and therefore are quite vulnerable to pathologies. Impaired filtration capacity of the kidneys can lead to the development of edema, increased blood pressure, and worsening of the condition of the kidneys. expectant mother and fruit.
Indications for the study are the following symptoms:
What does the Rehberg test determine? The results of the study help diagnose diseases such as:
How to take the Rehberg test correctly so that the test does not have to be done again? Results may be unreliable due to improper preparation or errors during urine collection.
On the eve and on the day of the study you must:
Important. Some drugs may influence the results of the study: furosemide, cortisol, corticotropin, thyroxine, methylprednisolone. If you are using them, talk to your doctor about whether you should stop taking them before your procedure.
Blood is taken from a vein and is carried out on an empty stomach.
Many patients are concerned about the question: how to properly collect urine for analysis? The study will require urine excreted during the day. Women should not collect material during menstruation.
They collect it like this:
Blood from a vein is donated either the same morning (after the bladder has been emptied of the first, “unnecessary” portion of urine), or on the day the daily urine collection ends.
To evaluate the results of the Rehberg test, there is a special calculation formula: F=(Cm/Cp)*V. F - glomerular filtration rate, Cm - creatinine level in urine, Cp - amount of creatinine in the blood, V - volume of urine excreted by the kidneys per minute in milliliters.
Rehberg test: normal values:
Deviations from the norm in the analysis results do not always indicate the presence of pathologies. The results may be distorted due to the consumption of large amounts of liquid or protein or too high-calorie foods, as well as after physical or emotional stress, burns. If there are no objective reasons for distorting the results, we are talking about the presence of diseases.
In general, deviations from the norm are allowed by 1-5 ml/min.
If the indicators in the analysis results are 15 or more units above the norm, this may indicate the presence of:
Test results 15 or more units below normal indicate the presence of renal failure.
The diagnosis is not made on the basis of only one Rehberg test. However, the results of the study allow one to suspect the presence of one or another pathology. To confirm pathologies, additional diagnostic procedures (laboratory tests, Ultrasound of the kidneys, etc.).
The Rehberg-Tareev test, or otherwise the clearance of endogenous creatinine, is one of diagnostic techniques making a diagnosis. It was developed by the Danish scientist Rehberg, and simplified by the Soviet Tareev.
Speaking in simple language, this test gives an idea of the body’s ability to cleanse itself of metabolic products that can cause harm. Laboratory examination is based on indicators of glomerular filtration rate (hereinafter GFR).
The technique is used in case of failure in the functioning of the excretory system, and also for diagnosing chronic diseases. The main signs that may indicate kidney problems and require testing are:
Sometimes such signs can occur during pregnancy or diabetes insipidus. In general, the Reberg-Tareev test makes it possible to promptly recognize the following pathologies:
GFR decreases as the disease progresses, with diabetes mellitus it happens very quickly.
In pregnant women, the uterus very often puts pressure on the kidneys due to its increase in size, so general analysis urine may have pathological values
To confirm the presence of a problem, Rehberg's study is used.
Any examination requires careful preparation; the reliability of the results depends on this. The Reberg-Tareev test requires urine collection per day.
The main preparation points are:
It is important to know that some medications can change GFR values. Among them are diuretics: Cortisone, Prednisolone, Thyroxine L, acetylsalicylic acid. The doctor will either adjust the dosage or stop the medication for a few days. In addition, women should tell the doctor about the presence of menstruation at the time of the test, because then the test can be postponed to another day.
Features of calculating glomerular filtration rate
On the eve of urine collection, you need to buy a container with a volume of two or three liters, as well as a small container of 100 ml. Before visiting the laboratory, urinary fluid is collected.
In the morning, drink half a liter of water, donate blood from a vein to the laboratory, and then begin collecting urine; before this and subsequent urination, the genitals are washed with warm water without detergents.
The first stream is flushed down the toilet, the rest of the urine is collected within 24 hours in a container, which is stored in a cold and dark place.
Extreme emptying of the bladder should occur no later than two hours before donating biological material. After this, 100 ml of urine is poured into a separate container, tightly closed with a lid and delivered to the laboratory.
The creatinine level is calculated in the blood donated by the patient. GFR is calculated taking this indicator into account. The sample formula gives a number that is compared with the norm.
So, F = (Cm/Сp)*V. At the same time, F is GFR, V is the amount of urine in milliliters excreted in 60 seconds; Cp – creatinine concentration in blood; Cm – concentration of creatinine in urine.
Doctors have adopted a certain conditional norm that takes into account the height and gender of the patient.
The main indicators of the norm are as follows:
If the result is not significantly deviated, then it is worth analyzing preparatory stage. There is a failure in the diet the day before, for example, eating a meal that is rich in proteins and spices. Perhaps there was some sport involved.
It is important to know that sometimes distorted results occur with burns and in the last trimester in pregnant women
If the digital values of this sample are high, then this may indicate hypertension, nephrotic syndrome, diseases of the endocrine organs (diabetes mellitus). Also, such values may be a consequence of taking Furosemide, Prednisolone, aminocarboxylic acid. Also protein products And physical activity increase GFR.
A reduced result indicates that the kidneys cannot properly cleanse the blood of toxins. Doctors after additional tests And instrumental examinations diagnose stones in urinary system, glomerulo-or pyelonephritis, kidney failure, pathology of the heart and blood vessels. Liver problems may be detected.
Reduced GFR occurs as a result of taking drugs such as thiazide diuretics and diazoxide. Depending on the GFR value, a moderate decrease in kidney function (GFR above 30 ml per minute), kidney failure (GFR - 15–30 ml per minute) is diagnosed. chronic failure kidneys (GFR does not exceed 15).
Carrying out a test cannot deliver accurate diagnosis, but calculates a violation of the kidneys. The main condition for the correct result of this study is compliance with the preparatory stage.
