Detection of acute kidney injury in premature asphyxiated neonates by serum neutrophil gelatinase-associated lipocalin (sNGAL)--sensitivity and specificity of a potential new biomarker.

INTRODUCTION: Acute kidney injury (AKI) is common in neonatal intensive care units (NICU). In recent years, every effort is made for early detection of AKI. Our hypothesis was that serum neutrophil gelatinase-associated lipocalin (sNGAL) may be a reliable screening test for early diagnosis of AKI in premature neonates after perinatal asphyxia. Therefore, our aim was to assess the diagnostic accuracy of sNGAL for AKI in premature asphyxiated neonates.

MATERIALS AND METHODS: AKI was defined in the third day of life (DOL 3) as a serum creatinine (sCr) increase ≥26.5 μmol/L from baseline (the lowest previous sCr). According to the increase of sCr, AKI patients were divided in AKIN1 (sCr increase up to 1.9 baseline) and AKIN2 (sCr increase from 2.0 to 2.9 baseline). sNGAL levels were measured on DOL 1, 3 and 7.

RESULTS: AKI was diagnosed in 73 (0.676) of 108 enrolled premature asphyxiated neonates. Sixty one patients (0.836) were classified in AKIN1 and 12 patients (0.164) in AKIN2. sNGAL reached the maximal concentrations on DOL 1 within 4 hours after admission to NICU, being higher in AKI compared with no-AKI group (160.8±113.1 vs. 87.1±81.6; P<0.001) as well as in AKIN2 compared with AKIN1 group (222.8±112.9 vs. 147.8±109.9; P<0.001). The best areas under the receiver operating characteristic curves (AUC) for prediction of AKI were 0.72 [95% (0.62-0.80) P<0.001] on DOL1 at 2h and 0.72 [95% (0.63-0.80) P<0.001] at 4th hour after admission respectively. The corresponding sNGAL cutoff concentrations were 84.87 ng/mL (sensitivity 69.0% and specificity 71.9%) and 89.43 ng/mL (sensitivity 65.7% and specificity 74.3%).

CONCLUSIONS: In premature asphyxiated neonates sNGAL measured within the first 4 hours of DOL 1 is predictive of the occurrence and severity of AKI. Therefore, plasma levels of NGAL may be used for early diagnosis of AKI in these patients.