A 34-week neonate is on phototherapy for neonatal jaundice. The TSB at 36 hours of age is 14 mg/dL. Total serum bilirubin rises to 18 mg/dL at 60 hours despite intensive phototherapy. The threshold at which exchange transfusion is indicated in this gestation and age (per AAP guidelines nomogram) is approximately:
- A When TSB exceeds the exchange transfusion threshold line on the hour-specific Bhutani nomogram (~20-24 mg/dL at 60 hours for 34 weeks) ✓
- B When TSB is >15 mg/dL regardless of age
- C When TSB is >3 mg/dL above the phototherapy threshold
- D When serum albumin-bilirubin molar ratio exceeds 8
Explanation
The AAP 2022 revised phototherapy and exchange transfusion guidelines use gestational age-stratified, hour-specific nomograms with individualized risk stratification (neurotoxicity risk factors). For a 34-week neonate at 60 hours, the exchange transfusion threshold is approximately 20-22 mg/dL (varies with neurotoxicity risk factors). Exchange transfusion is indicated when TSB reaches or exceeds the ET threshold line despite intensive phototherapy, or when clinical signs of acute bilirubin encephalopathy appear. A fixed threshold of >15 mg/dL or >3 mg/dL above phototherapy threshold is too simplistic and not guideline-based. The albumin-bilirubin ratio is supplementary but not the primary trigger criterion.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.