During a newborn assessment at 24 hours of life, the nurse notes the baby has jaundice visible below the umbilicus. How should the nurse prioritise this finding?

NEONATAL JAUNDICE ZONATION (Kramer's Rule): Zone 1 — head and neck: suggests lower bilirubin (<5-6 mg/dL); Zone 2 — to umbilicus: approximately 5-12 mg/dL; Zone 3 — below umbilicus to knees: approximately 8-16 mg/dL; Zone 4 — below knees to ankles: approximately 11-18 mg/dL; Zone 5 — palms and soles: ≥15-20 mg/dL; CLINICAL NOTE: Kramer's rule has limitations — dark skin tone makes clinical assessment unreliable; transcutaneous bilirubin (TcB) and serum bilirubin (TSB) are more accurate; SIGNIFICANCE OF ZONE 3+: Jaundice below the umbilicus requires immediate assessment — high bilirubin can cause kernicterus (permanent brain damage) if untreated; TREATMENT: Phototherapy is the primary treatment; exchange transfusion for severe cases; TIMING: Jaundice appearing in first 24 hours (pathological) is more serious than jaundice appearing 2-4 days (physiological).