α2-Microglobulin predicts renal injury in asphyxiated neonates

Abstract

ObjectiveThe aim of the study was to predict early renal injury in asphyxiated neonates by measuring urinary level of b2 -microglobulin (b2 MG).Backgroundb2 MG has a molecular weight of 12 000 and it belongs to the light chain part of membrane-bound HLA antigens. It consists of two polypeptide chains, a heavy chain with antigenic structure and a light chain. Urinary b2 MG, specific urinary marker of renal tubular damage, can identify renal damage from asphyxia within 48 h of the insult.MethodsThis study included 50 asphyxiated newborns along with 35 weight-matched and gestational age-matched normal neonates as controls. First, voided urinary samples were collected within the first day of life and values of urinary b2 MG was determined by immunometric enzyme immunoassay.ResultsIn this study, we found that acute kidney injury occurred in 56% of asphyxiated neonates. The remaining 44% patients had subclinical tubular proteinuria. Urea and creatinine levels among patients were significantly higher on day 4 than on day 1. We found that, at the optimum cutoff level of 11.9 mg/ml of urinary b2 MG, the sensitivity, specificity, and accuracy of predicting renal injury in asphyxiated neonates were found to be 86, 68, and 74%, respectively.ConclusionIncidence of acute kidney injury in asphyxiated neonates was 56%. b2 MG is a sensitive and accurate marker of renal insult among these patients. Studies on other biomarkers such as NGAL, KIM-1, and cystatin C may be performed to evaluate their role in predicting renal injury.