Abstract: Objective To study clinical applications of direct antiglobulin test (DAT) and ratio of total bilirubin to albumin (B/A) in newborns with severe hyperbilirubinemia resulting from ABO hemolytic disease of the newborn (ABO-HDN). Methods The neonates diagnosed with ABO-HDN in Wuhan Children's Hospital from June 2020 to December 2021 were grouped into the high-risk group and the low-risk group based on the peak value of total bilirubin of individuals. The correlations of DAT and B/A with severe hyperbilirubinemia caused by ABO-HDN were singly or conjointly analyzed between groups. Results Among 270 patients, 69 were confirmed positive in the DAT assay. The optimum cutoff values of receiver operating characteristic curve (ROC) for correlations of DAT and B/A with severe hyperbilirubinemia caused by ABO-HDN were±and 8.84. Binary logistic regression analysis showed that the peak values of total bilirubin (OR 0.970; 95% CI 0.962~0.987), B/A (OR 6.152; 95% CI 3.593~10.535), DAT(±) (OR 0.106; 95% CI 0.018~0.646), DAT (1+) (OR 0.280; 95% CI 0.116~0.674), and DAT (2+) (OR 0.152; 95% CI 0.049~0.472) were significantly and independently correlated with the severity of hyperbilirubinemia (P<0.05). Areas under the curve (AUC) of ROC for correlations of DAT, B/A and both of them with severe hyperbilirubinemia were 0.621, 0.740 and 0.750, respectively. Conclusion DAT or B/A seems to be a competent predictor of severe hyperbilirubinemia caused by ABO-HDN, which could be enhanced when the two indicators are combined.

Key words: Direct antiglobulin test, Ratio of total bilirubin to albumin, ABO hemolytic disease of the newborn, Neonatal hyperbilirubinemia