RESUMO
Cystatin C is an endogenous marker of renal function. Normal reference values have been documented in neonates outside Africa, but no study has been documented in African neonates. With reports that race may affect serum cystatin C values, this study was carried out to generate normal values in apparently healthy term neonates at birth and three days of life neonates in Nigeria. This was a hospital-based prospective study. A cohort of 120 apparently healthy term neonates were recruited at birth. Serum cystatin C was measured from the cord blood at birth and venous blood when they were three days old using enzyme-linked immunosorbent assay (ELISA) method. The mean serum cystatin C values for cord blood and 3rd day venous samples were 1.67 ± 0.52 mg/L and 1.62 ± 0.52 mg/L, respectively (P = 0.87). The cord blood and 3rd day serum cystatin C values for males were 1.67 ± 0.47 mg/L and 1.68 ± 0.51 mg/L, respectively (P = 0.77) and the values for females were 1.68 ± 0.56 mg/L and 1.58 ± 0.52 mg/L, respectively (P = 07.22). The serum cystatin C levels were similar among the different birth weight groups and gestational age (P >0.05). The cord blood and 3rd day serum cystatin C values were similar. Serum cystatin C values were independent of gender and birth weight of neonates. The values of serum cystatin C in Nigerian neonates were comparable to that reported for neonates in other regions of the world. It is recommended that ELISA technique may be reliably used to measure serum cystatin C levels in neonates.