Glucose-6-phosphate dehydrogenase activity in term and near-term, male African American neonates

Background: We determined values for glucose-6-phosphate dehydrogenase (G-6-PD) activity in African American neonates. Methods: G-6-PD activity was measured on umbilical cord blood from term and near-term healthy, male neonates. Neonates were stratified according to the number of neonates for each numerical unit of G-6-PD activity. Corrected end tidal carbon monoxide (ETCOc), a non-invasive index of hemolysis, was performed on each neonate. At least one predischarge transcutanous bilirubin determination was performed. Results: Five hundred neonates were studied. Two subpopulations were apparent, with no overlap between the subgroups. Mean value for the 64 (12.8%) infants with the lower values (G-6-PD deficient) was 2.7±1.1 U/g Hb, range 0.4-6.6 U/g Hb, while that for the 436 neonates with the higher values (G-6-PD normal) was 21.8±2.9 U/g Hb, range 14.5-33.8 U/g Hb. No significant differences in activity were noted between those neonates <37 weeks gestational age and those >37 weeks. Enzyme activity in the lower range in both groups was not related to the development of hyperbilirubinemia. G-6-PD enzyme activity did not correlate with ETCOc values either for the entire cohort or for the individual subsets. Conclusions: G-6-PD-deficient neonates formed a separate subgroup from those with normal enzyme activity. The data supplied should facilitate interpretation of G-6-PD test results.