Creatinine

A product of energy metabolism in muscle tissues. Creatinine is formed in muscle fibers, so its amount depends on muscle mass. The function is to provide the muscles with energy material. Since the chemical precursor creatine is formed in the liver, its function also has an effect on creatinine concentration. 

A distinctive feature of creatinine is the lack of reabsorption in the kidneys (many substances are not completely excreted by the kidneys, a certain amount enters back into the bloodstream). This factor allows you to determine the condition of the renal tissue as accurately as possible. 

Knowing how much creatinine there is in the blood and how much should be released, doctors prescribe a blood and urine test for creatinine according to a special scheme. Next, the ENDOGENOUS CREATININE CLEARANCE is calculated using the formula (Rehberg-Tareev sample). Its decrease signals a violation of kidney function. The increase indicates a pathology such as chronic glomerulonephritis with nephrotic syndrome. 

Modern clinical pharmacologists select the right dosage of medication, taking into account the clearance of endogenous creatinine. Thus, it is most advisable to take a blood and urine creatinine test together.