Carboxyhemoglobin levels were higher in patients with hemolytic disease (Rh isoimmunization) than in normal infants born of nonsmoking mothers, both at birth and during the first day of life. In these patients, postnatal carboxyhemoglobin levels correlated with the rate of bilirubin rise and the need for exchange transfusion. Nine infants with idiopathic hyperbilirubinemia and normal carboxyhemoglobin levels had no evidence for increased hemolysis, whereas seven jaundiced infants with elevated carboxyhemoglobin concentrations had conditions likely to cause hemolysis.
Carboxyhemoglobin determination may be helpful in (1) predicting the need for exchange transfusion in erythroblastotic infants and (2) differentiating hemolytic from nonhemolytic causes of neonatal jaundice.
Alden ER, Lynch SR, Wennberg RP. Carboxyhemoglobin Determination in Evaluating Neonatal Jaundice. Am J Dis Child. 1974;127(2):214-217. doi:10.1001/archpedi.1974.02110210064008