The early predictive value of Cys-C, lactic acid, and urinary microglobulins in acute kidney injury following neonatal asphyxia

Background: Neonatal asphyxia is a critical perinatal complication closely associated with acute kidney injury (AKI), which seriously affects the prognosis of neonates. Early and accurate biomarkers are urgently needed for timely identification and risk prediction of AKI in asphyxiated newborns. This study aimed to explore the predictive value of cord blood and urinary renal injury markers for neonatal AKI after asphyxia.

Methods: A total of 85 neonates with asphyxia admitted to Jinjiang City Hospital (Fujian Branch of Shanghai Sixth People’s Hospital) from January 2023 to March 2025 were analyzed. All patients underwent renal injury marker testing, including cord blood cystatin C (Cys-C) and lactic acid, urinary β2-microglobulin (β2-MG), transferrin (TRF), and α1-microglobulin (α1-MG). Neonates were classified into an AKI group and a non-AKI group based on AKI occurrence. Levels of serum Cys-C, lactic acid, and renal injury marker were compared between the two groups. The predictive value of serum Cys-C, lactic acid, urinary β2-MG, TRF and α1-MG levels, and their individual or combined effects on neonatal AKI was evaluated.

Results: The incidence of AKI in asphyxiated neonates was 42.35% (36/85). The AKI group had a significantly higher proportion of severe asphyxia compared to the non-AKI group (P<0.05). Blood Cys-C, lactic acid, urinary β2-MG, TRF and α1-MG levels were significantly elevated in the AKI group (P<0.05). The combination of blood Cys-C, lactic acid levels with urinary β2-MG, TRF, α1-MG yielded a sensitivity of 75%, a specificity of 98.0% and an area under the curve (AUC) of 0.909 for predicting AKI in asphyxia newborns, both significantly higher than individual indicators (P<0.05), The specificity was-consistent to that of single indicators.

Conclusions: The study shows that Cys-C, lactic acid, urinary β2-MG, TRF, and α1-MG are effective early indicators for monitoring renal injury after neonatal asphyxia resuscitation. Each of these indicators has predictive value for AKI in asphyxia newborns, with the combined five indicators demonstrating even higher predictive value, providing a more accurate assessment of early renal function status in such infants.