OBJECTIVETo study the value of carboxyhemoglobin (COHb) in the diagnosis of neonatal jaundice.

METHODSThis study consisted of 189 patients with neonatal jaundice due to hemolytic disease (n=75), infectious disease (n=52), intracranial hemorrhage (n=32) and breast-milk feeding (n=30). One hundred and forty-two neonates without pathological jaundice that were gestational age, postnatal age- and birth weight-matched were used as the Control group. The level of arterial capillary blood COHb was detected by a 270 CO-oximeter connected to an 800 series system. Total serum bilirubin (STB) content was measured using an Abbott Spectrum CCX chemistry analyzer. The levels of COHb and STB were measured at baseline, and again in patients with jaundice due to hemolytic disease after intravenous gammaglobulin treatment for 2 days.

RESULTSThe levels of COHb [(3.64 +/- 0.83)%] and STB (330.84 +/- 77.15 micromol/L) in patients with jaundice due to hemolytic disease were significantly higher than those measured in the Control group [COHb (2.38 +/- 0.35) %; STB 130.18 +/- 32.86 micromol/L] (P < 0.01). The levels in patients with jaundice due to intracranial hemorrhage were also significantly higher than those in the Control group [COHb (2.48 +/- 0.53) % vs (2.24 +/- 0.32) %; STB 184.15 +/- 29.35 micromol/L vs 112.11 +/- 17.45 micromol/L; P < 0.05]. The patients with jaundice due to infectious disease or breast-milk feeding only demonstrated higher levels of serum STB (P < 0.01) while COHb levels were not different compared with the Control group. The patients with jaundice due to hemolytic disease or intracranial hemorrhage presented with hemolytic unconjugated hyperbilirubinemia and had significantly higher COHb levels and lower STB levels than those patients with nonhemolytic unconjugated hyperbilirubinemia (caused by breast jaundice) (P < 0.01). The levels of COHb [(2.68 +/- 0.51) %] and STB (230.18 +/- 42.96 micromol/L) in patients with jaundice due to hemolytic disease decreased markedly after intravenous gammaglobulin treatment (P < 0.01).

CONCLUSIONSThe COHb level can be used as a supplementary indicator of increased bilirubin production. The elevation of COHb can be useful in the diagnosis of neonatal jaundice since COHb is elevated in hemolytic disease and intracranial hemorrhage.