Relationship between carboxyhemoglobin levels and indirect hyperbilirubinemia in preterm newborns

Bahar Y. F., Ongun H., Kıhtır Z., Çelik K., Arayıcı S.

Türkiye Çocuk Hastalıkları Dergisi, cilt.20, ss.1-7, 2026 (TRDizin)

Özet

Objective: Neonatal jaundice, caused by elevated bilirubin levels, may lead to severe neurological complications, particularly in preterm infants. The aim of this study was to evaluate the predictive value of early carboxyhemoglobin (COHb) levels for identifying indirect hyperbilirubinemia and the need for phototherapy in preterm neonates.Materials and Methods: This retrospective study included 297 preterm infants admitted to the neonatal intensive care unit (NICU). COHb, bilirubin, and related laboratory parameters were evaluated at 0–6 hours, 24 hours, and 48–96 hours after birth. Statistical analyses included the Mann–Whitney U test, Spearman correlation analysis, receiver operating characteristic (ROC) curve analysis, and logistic regression.Results: Among 297 preterm newborns, 151 (50.8%) required phototherapy. Early COHb levels showed only very weak correlations with subsequent bilirubin concentrations. COHb levels at 0–6 hours and 24 hours demonstrated poor discriminatory performance for phototherapy requirement, with AUC values of 0.560 and 0.583, respectively. Neither measurement was independently associated with phototherapy requirement in multivariable analyses, whereas birth weight <2000 g remained an independent determinant in both models.Conclusion: Although early COHb levels showed weak correlations with indirect bilirubin levels in preterm neonates, they were not reliable independent predictors of phototherapy requirement. These findings suggest that COHb has limited clinical utility as a standalone biomarker for guiding treatment decisions.Keywords: Carboxyhemoglobin, hyperbilirubinemia, neonate, phototherapy, preterm infant