The Rehberg test is a laboratory test that evaluates kidney function by determining glomerular filtration rate (GFR) and tubular reabsorption. For analysis, daily urine is collected and blood is donated to determine creatinine concentration. This test helps to diagnose kidney diseases, the stage of their damage and monitor the effectiveness of treatment. 

Creatinine is filtered from the blood by the kidneys, and a small amount of it is actively excreted in the urine. Tubular creatinine reabsorption is minimal. If the filtering capacity of the kidneys is insufficient, then the creatinine level in the blood increases. Knowing the levels of creatinine in urine and blood, you can calculate creatinine clearance, which reflects the level of glomerular filtration. Creatinine clearance (from English clearance – "purification", i.e. purification from creatinine, its excretion) is the amount of blood that the kidneys can clear of creatinine in one minute. In a healthy young man, it is about 125 ml per minute, which means that his kidneys purify 125 ml of blood from creatinine every minute.

The glomerular filtration rate is the sum of the filtration levels in all functioning nephrons. This indicator allows you to determine the number of these nephrons in the kidneys. It has important clinical significance because it is the main characteristic of kidney function.

In cases of severe renal impairment, creatinine clearance increases because a larger fraction of creatinine is released during active secretion. If the patient has a low glomerular filtration rate, the attending physician will develop an additional examination program to determine the cause of this pathological condition. Systematic determination of creatinine clearance allows the doctor to monitor changes in the patient's kidney function over time and adjust drug therapy depending on the data obtained.

What is the research used for?

·To assess kidney function

·to assess the dynamics of the course of renal diseases

·to assess kidney function in patients taking nephrotoxic drugs

·to detect severe dehydration