A 4-day-old term infant has unconjugated hyperbilirubinemia (TSB 19 mg/dL). Phototherapy is initiated. Which of the following factors would indicate a need for EXCHANGE transfusion rather than intensified phototherapy alone?
- A TSB 18 mg/dL in a term infant with minor ABO incompatibility
- B Positive direct Coombs test alone regardless of bilirubin level
- C TSB ≥25 mg/dL in a healthy term infant at 72 hours of age, or rising >0.5 mg/dL/hour despite phototherapy ✓
- D Any bilirubin above 20 mg/dL in an infant >48 hours of age
Correct answer: C. TSB ≥25 mg/dL in a healthy term infant at 72 hours of age, or rising >0.5 mg/dL/hour despite phototherapy
Explanation
Exchange transfusion thresholds are defined by the AAP/Bhutani nomogram and depend on gestational age, hours of life, and risk factors. For a term healthy infant, exchange transfusion is indicated when TSB reaches approximately 25 mg/dL at 72 hours, or when TSB is rising faster than 0.5 mg/dL/hour despite intensive phototherapy, or when there are neurological signs of bilirubin encephalopathy. A positive Coombs alone, or bilirubin at 18–20 mg/dL in a term infant, typically requires phototherapy intensification, not exchange transfusion.
Reference: Ghai Essential Pediatrics, 10th ed.
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