Reference intervals for serum cystatin C and serum creatinine in adults.

The aim of this study was to establish reference intervals for cerum cystatin C and serum creatinine in adults. Blood samples were collected from 270 healthy blood donors (135 men and 135 women between 20 and 65 years old with 15 men and 15 women in each five-year-interval). Serum cystatin C was analyzed using an automated particle-enhanced immunoassay (DAKO Cystatin C PET kit) on the Cobas Mira S analyzer. Serum creatinine was analyzed using the Vitros Creatinine Slide, an enzymatic method on the Vitros 950 chemistry analyzer. The calculated reference intervals for serum cystatin C were 0.62-1.15 mg/l in women (median 0.84 mg/l, range 0.56-1.29 mg/l) and 0.51-1.25 mg/l in men (median 0.87 mg/l, range 0.42-1.39 mg/l). The Mann-Whithey U-test revealed no gender-related difference for cystatin C (p = 0.48). A common reference interval in women and men was calculated to be 0.54-1.21 mg/l (median 0.85 mg/l, range 0.42-1.39 mg/l). The non-parametric reference interval for serum creatinine was 57-95 mumol/l in women (median 72 mumol/l, range 44-105 mumol/l) and 69-111 mumol/l in men (median 89 mumol/l, range 58-123 mumol/l).