Neonatal jaundice: unconjugated hyperbilirubinaemia: Viva

Branch 1: Risk assessment and interpretation

The candidate should immediately recognise that jaundice within the first 24 hours of life is always pathological and requires urgent evaluation. A TSB of 220 micromol per litre at 20 hours in a term infant is significantly elevated for age and falls in the high-risk zone on the hour-specific nomogram. The maternal blood group O raises the possibility of ABO incompatibility if the infant is group A or B. ^[3]

The candidate should list the risk factors: onset before 24 hours, maternal blood group O (potential ABO incompatibility), and any additional risk factors to be elicited from the history including gestational age, feeding adequacy, weight loss, cephalohaematoma or bruising, family history of jaundice or G6PD deficiency, and ethnic background. The investigation should include a haemolytic workup: DAT, blood group, full blood count with reticulocyte count, peripheral film, and G6PD assay if at-risk heritage. ^[3]

The 2022 AAP guideline uses gestational-age-specific threshold curves with a neurotoxicity risk modifier. For a 39-week well infant with no haemolysis, this bilirubin may or may not meet the phototherapy threshold depending on the exact age in hours. If the DAT is positive (haemolysis confirmed), the infant is classified as higher neurotoxicity risk, which lowers the threshold. ^[1]