CREA | Creatinine

Creatinine is one of the most important indicators of glomerular filtration and kidney function. When the filtering function of the kidneys is impaired, the concentration of creatinine in the serum increases. Creatinine is produced in the muscles and after entering the blood is filtered in the glomeruli of the kidneys. The concentration of creatinine in the serum of a healthy person is a fairly constant value, since the rate of its excretion in the kidneys varies only by 10-15%, and the synthesis is proportional to the muscle mass. Creatinine filtration depends on the amount of functioning glomeruli. If the amount of functionally active glomeruli decreases, then the serum creatinine concentration increases. With aging, glomerular filtration and muscle mass decline roughly proportionally, so serum creatinine remains virtually unchanged. Serum creatinine levels may vary from individual to individual, but for any healthy individual, it is a relatively constant value at various points in time. The main indications for creatinine determination are to assess glomerular filtration, the amount of functionally active glomeruli and the degree of severity of kidney disease.

Creatinine is a more specific kidney test, but may be less sensitive in some cases of kidney disease. Only when the serum creatinine concentration rises above 250µmol/l can it be said that the concomitant increase in urea concentration is related to renal insufficiency.

Creatinine is the end product of creatine metabolism. Creatinine formation in the body is highly dependent on total muscle mass. Therefore, if the patient's weight is very low, if he is diagnosed with hypothyroidism or another cause that lowers creatinine concentration, this indicator may not fully reflect the filtration function of the kidneys.

Creatinine increases with kidney failure, urinary tract obstruction, increased muscle mass, muscle breakdown. Creatinine decreases with low muscle mass, muscular dystrophy, pregnancy, corticosteroids.

Recommendations:

• It is recommended to carry out prophylactically once a year, for disease diagnosis and treatment control it is carried out periodically according to the doctor's instructions.
• The results of the test are influenced by medications, diet, fasting, kidney diseases (glomerulonephritis, pyelonephritis, acute renal tubule necrosis), urinary tract obstruction, diabetes, hyperthyroidism, pregnancy.
• To take the test, it is necessary to arrive after fasting for 8-12 hours.