Objective. To assess the validity of predischarge serum bilirubin values in
determining or predicting hyperbilirubinemia in glucose-6-phosphate dehydr
ogenase (G-6-PD)-deficient neonates, and to facilitate appropriate discharg
e planning.
Methods. Serum total bilirubin values were determined between 44 and 72 hou
rs of life in a cohort of term, healthy neonates at high-risk for G-6-PD de
ficiency but with no other risk factors for hyperbilirubinemia. Percentile-
based bilirubin nomograms were constructed for G-6-PD-deficient infants and
normal infants according to age at sampling. The incidence of hyperbilirub
inemia (serum bilirubin value greater than or equal to 256 mu mol/L [15 mg/
dL]) for each group was determined according to the percentiles for that gr
oup.
Results. In both G-6-PD-deficient neonates (n = 108) and control neonates (
n = 215) with serum bilirubin values <50th percentile for age, the incidenc
e of hyperbilirubinemia was low in the G-6-PD-deficient neonates, with no m
easurable incidence in the controls. The incidence of hyperbilirubinemia be
came clinically consequential, and significantly higher in the G-6-PD-defic
ient groups, when the percentiles were greater than or equal to 50: for tho
se in the 50% to 74% range the incidence was moderate (23%) for the G-6-PD-
deficient and small (7%) for the control infants (relative risk, 3.29; 95%
confidence interval, 1.01-10.67). Among those infants greater than or equal
to 75th percentile, 82% of the G-6-PD-deficient infants, compared with 25%
of the control infants, were either already hyperbilirubinemic at the time
of screening or subsequently developed hyperbilirubinemia (relative risk,
3.23; 95% confidence interval, 1.99-5.24).
Conclusions. Timed, predischarge serum bilirubin screening can be used to i
dentify G-6-PD-deficient neonates at low, intermediate, or high-risk of dev
eloping severe neonatal hyperbilirubinemia, and thus offer a selective appr
oach to the discharge and follow-up surveillance of these infants.