J. Đelmiš

Pediatric nephrologists are in permanent search for ideal marker of renal function. Unfortunately there is still no simple and accurate test for rapid estimation of kidney function. Clearance tests require either laborious collection of timed urine and blood samples, or intravenous injection of various substances. Serum concentration of creatinine is widely used for assessment of glomerular filtration rate (GFR). The production of creatinine is changed by gender, age and muscle mass and therefore is not excellent marker of GFR in children. Common tests to evaluate GFR and renal ability to concentrate and dilute urine, as well as renal ability of acidification of urine are presented.