Background: Serum creatinine (SCr) is widely used to test renal function. SCr at birth is strongly affected by maternal SCr and does not reflect the renal function of the neonate. Serum cystatin C (CysC) has been used as an indicator of glomerular filtration rate in adults and children. However, CysC has not been widely used to evaluate kidney function in neonates until now.
Results: The cord blood CysC and SCr of ten neonates was measured at birth. The CysC levels of four patients without impaired renal function were between 1.26 and 1.53 mg/L. The CysC level in one case whose mother was diagnosed with chronic kidney disease was not elevated (1.60 mg/L), although the patient’s SCr level was elevated (2.25 mg/dL). The CysC levels of three patients with acute kidney injury due to asphyxia were slightly higher (1.78 to 2.17 mg/L) than those in patients without acute kidney disease. The CysC levels of two patients diagnosed with renal failure were substantially higher (4.09 and 7.07 mg/L) than those of patients without renal failure.
Conclusion: CysC shows potential as a useful marker to evaluate the kidney function of neonates at birth, as CysC is not affected by maternal CysC.
Mariko Sawada, Kazutoshi Ueda, Kanako Yoshizaki, Satoko Tokumasu, Masamichi Kubota, Akihito Takahashi, Masaaki Hasegawa and Shinichi Watabe