A 2-day-old neonate born at 35 weeks has a total serum bilirubin of 14 mg/dL. The Coombs test is negative and the blood group is O+. The mother is B+. A peripheral smear shows microspherocytes. Which enzyme assay would MOST likely identify the aetiology of haemolysis in this infant?

• A Glucose-6-phosphate dehydrogenase ✓
• B Pyruvate kinase
• C Hexokinase
• D Glutathione reductase

Explanation

G6PD deficiency is the most common inherited enzyme deficiency causing neonatal jaundice in India. The presentation — preterm male, indirect hyperbilirubinaemia, negative Coombs, microspherocytes on smear — points to G6PD deficiency. G6PD protects red cells from oxidative haemolysis; deficiency causes haemolysis triggered by oxidative stress or even without obvious trigger in neonates. Pyruvate kinase deficiency can cause haemolysis but is far less common.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.