Cystatin is reported in the literatura with increasing frequency as a new reliáble parameer for estimates of glomerular filtration. The authors examined Cystatin C by the PET method of DAKO Co. in 151 patients from the nephrological out-patient clinic. 91 patients had normal renal functions, 60 suffered from renal insufficiency of different severity. Between Cystatin C and glomerular filtration assessed by creatinine clearance was a Glose correlation, R = -0.787 according to Pearson. The authors evaluated separately a group of 36 patients with glomerulonephritis, 34 diabetic patients with diabetic nephropathy, 38 patients with tubulointerstitial nephritis and 43 subjects with other kidney diseases. The groups did not differ significantly when compared with the whole group nor mutually (p = n.s.). The authors of the study conňrmed that a good correlation of Cystatin with creatinine filtration is not intluenced by the type of basic nephrological disease. The effect of administration of insulin, antihypertensive drugs, cyclosporin A and glucocorticoids was not proved in the investigated group.The published method is accurate, not demanding from the technical aspect.The examined subject is not reatricted by conditions ensuring the accuracy of assessment and seems thus useful and perspective for nephrological patients.

        Key words: Cystatin C - Glomerular filtration