Severe hyperbilirubinemia prediction in neonates using a newly developed cord blood index (Çapa index): a promising tool: A retrospective cohort pilot study.

Prevention of hyperbilirubinemia, among common reasons for outpatient visits and hospital readmissions during the neonatal period, depends on early diagnosis and effective treatment. Thus, discovering novel indices and parameters to predict severe hyperbilirubinemia is critical. The presence of hemolysis risk factors in newborns is not a prerequisite for treatment in most cases. We aimed to seek the role of a novel index (Çapa index), developed using umbilical cord blood carboxyhemoglobin (COHb) and total bilirubin levels, in predicting severe hyperbilirubinemia in the early neonatal period. In total, 290 term neonates were included in the present study, of which 171 were direct antiglobulin test positive with A, B, and O blood group system and/or rhesus factor incompatibility, and 119 were healthy controls without blood group incompatibility, sepsis, asphyxia, respiratory problems, pathologic weight loss, congenital anomaly, or need of intensive care. Çapa index was calculated by multiplying COHb (%) and total bilirubin (mg/dL) levels in umbilical cord blood and compared between the groups to predict its role in treatment requirements. COHb, bilirubin, and Çapa index were higher in the disease group than in healthy controls. In the disease group, cord blood bilirubin levels in the neonates needing phototherapy (PT) were unexpectedly significantly lower. In contrast, the COHb and Çapa index were higher than the ones without a need for treatment. In the disease group, the Çapa index had a significant predictive value in estimating PT requirements (area under the curve = 0.94). Standard hemolysis criteria have limited predictive value in the progression of hyperbilirubinemia. Çapa index, calculated as a practical biochemical index using umbilical cord blood COHb and bilirubin levels, can be a promising parameter in predicting severe hyperbilirubinemia and PT requirements in neonates.