Objective: to determine diagnostically significant values of cystatin C (CsC) serum concentration for differentiating of chronic kidney disease (CKD) 1-3 st. (3a and 3b) and determining the categories of patients with prognostically adverse forms of renal disease.
Research materials and methods. Diagnostically significant values of CsC were determined in 132 patients with CKD 1-3 st. (3a and 3b) aged from 2 to 17. A more in-depth study of the serum CsC content in different nephropathy forms was made.
Results and discussion. The CsC level in patients with CKD 3a st. was 1.41±0.02 mg/l, this being significantly lower than the values of the corresponding indicator obtained in patients with CKD 3b (1.97±0.11 mg/l) (p<0.001) and significantly higher than the values obtained in patients with CKD 1 st., CKD 2 st. (p<0.001). The analysis of the blood serum CsC content in the study patients demonstrated that the highest level of CsC 1.59±0.2 mg/l was recorded in patients with bilateral ureterohydronephrosis, and this significantly differed from the values obtained in patients with unilateral ureterohydronephrosis (p<0.05), unilateral or bilateral third-degree vesicoureteric reflux (VUR), renal dystopia, chronic glomerulonephritis (CGN) of nephrotic form, CGN of hematuric form and CGN with isolated urinary syndrome (p<0.01). A high risk of CKD progression was found in patients with polycystic kidney disease who had a serum CsC level of 1.2±0.093 mg/l and in 16 patients with chronic tubulo-interstitial nephritis who had a history of acute kidney injury - 1.2±0.1 mg/l, this being significantly different from the values of this indicator obtained in patients with chronic uncomplicated pyelonephritis and hematuric CGN (p<0.001), renal dystopia and unilateral third-degree VUR (p<0.01), bilateral third-degree VUR and nephrotic CGN, and CGN with isolated urinary syndrome (p<0.05).
Summary. Cystatin C is a marker for determining and differentiating of CKD 1-3(3a and 3b) stages and sub-stages, for determining the category of patients with prognostically adverse forms of renal pathology, such as bilateral ureterohydronephrosis, polycystic kidney disease, chronic tubulointerstitial nephritis as a consequence of acute kidney injury.