Abstract 1395

Background: ABO isoimmunization, positive (+) direct Coombs test, is considered a risk factor for excessive hyperbilirubinemia. However, liver maturity influences the contribution of the increased bilirubin production. The Bilirubin Nomogram (Pediatrics, 1999) encompasses both bilirubin production and excretion. Objective: To assess, in healthy term and near-term newborns with + Coombs test, the risk of hyperbilirubinemia based on the nomogram and the known clinical risk factors. Methods: We followed babies determined to have a + direct Coomb's test (routinely performed for all babies born to mother's with blood type O) and/or who were universally screened for bilirubin at discharge or detection of jaundice. Intervention for jaundice was based upon physician discretion. Based on the pre-phototherapy peak serum bilirubin values, babies were assigned to high-risk (>95th percentile for age). intermediate-risk (40 to 95th percentiles for age) or low-risk (>40th percentile for age) zones. Results: From 11,015 deliveries at PaH (1996-1998), 644 were deemed healthy well babies and had + Coombs test. Of these, 553 (mean BW = 3.34kg and mean GA = 38.9 wks) were followed for 7-10 days age. Relation to risk zones of the nomogram to some of the demographic risk factors: near-term (% <37wks), breast-feeding, assisted vaginal delivery (AVD: vacuum/forceps), sibling with jaundice and east-Asian descent, as well as phototherapy initiation and length of hospital stay (LOS, days) are shown below Conclusion: Both universal screening and early risk-assessment for excessive hyperbilirubinemia by tracking babies on the Bilirubin Nomogram may more effectively target the clinical management including the initiation and weaning of phototherapy.(Table)

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