Screening for neonatal hyperbilirubinaemia and ABO alloimmunization at thetime of testing for phenylketonuria and congenital hypothyreosis

In a population-based study including 2463 infants, serum bilirubin measure ments were added to the neonatal screening programme for phenylketonuria an d congenital hypothyreosis. This screening programme detected 11/17 (65%) o f infants with serum bilirubin levels >350 mu mol l(-1), of whom 7 (3 per 1 000) were readmitted from home (6 treated with phototherapy). A total of 13 9 infants (5.6%) received phototherapy. Maternal blood type O occurred sign ificantly more often in term infants treated (30/54; 55.6%) compared with p reterm infants treated (32/85; 37.6%) and with blood type O occurrence in t he total population of mothers (906/2426; 37.3%) (p < 0.05). The blood type constellations mother O/infant A or B showed a sensitivity of 64%, specifi city 65%, positive predictive value 12% and a negative predictive value of 96% for the requirement of phototherapy for the whole material. Exchange tr ansfusion was not required in any of the infants. No infant developed bilir ubin encephalopathy (kernicterus). Adding bilirubin to a neonatal screening programme detects some cases with unexpectedly high bilirubin levels in ne ed of intervention. Routine ABO blood typing of pregnant women, ABO cord bl ood typing and Coombs' test in infants of mothers with blood type O cannot be recommended because of low positive predictive value for the requirement of intervention (phototherapy) by these tests.