For term infants, specific indications are serum bilirubin ≥ 20 mg / dL (≥ 342 micromol / L) at 24 to 48 hours or ≥ 25 mg / dL (≥ 428 micromol / L) at > 48 hours and failure of phototherapy to result in a 1 - to 2-mg / dL (17 - to 34-micromol / L) decrease within 4 to 6 hours of initiation or at the first clinical signs of kernicterus regardless of bilirubin levels.