Reference values of serum cystatin-C for full-term and preterm neonates in Istanbul.

Objective: To determine the level and distribution of Cystatin C values in full-term and preterm healthy neonates for the purpose of diagnosis and follow-up of renal diseases of the neonates.
Methods: Eighty-eight newborn infants, including 55 preterm and 33 term born in the authors' hospital having no urinary tract pathology, symptoms or signs during prenatal and postnatal follow-up, were studied .
Results: There were 25 neonates born between gestational wk of 28 and 32 (Group 1), 30 neonates born between gestational wk of 33-36 (Group 2) and 33 neonates born after gestational wk of 37 (Group 3). Average cystatin C values were determined to be 1.41 mg/l, 1.22 mg/l and 1.21 mg/l for Group 1, Group 2 and Group 3, respectively.
Conclusions: Evaluation of cystatin C can be effective for follow-up of renal pathologies, because it is not affected by gender, body weight and muscle mass and has a constant production rate.