Bilirubin action thresholds for a term neonate (≥38 weeks, no risk factors),
plotted against age in hours. The phototherapy line starts around
6 mg/dL at birth and rises to ~18 mg/dL at day 6. The exchange transfusion line
runs approximately 5 mg/dL higher throughout. Thresholds are lower for preterm infants,
those with haemolysis, and those with other risk factors — always use the gestational-age
and risk-stratified nomogram in practice.