G6PD Level of 1.40 U/g Hb in a 2-Month-Old Boy
A G6PD level of 1.40 U/g Hb in a 2-month-old boy is abnormally low and indicates G6PD deficiency, as it falls below the reference level of 2.2 U/g Hb. 1
Understanding G6PD Deficiency in Infants
- G6PD deficiency is one of the most common enzyme disorders in humans and an important cause of neonatal jaundice 2
- In infants under 30 days of age, normal G6PD enzyme activity levels are approximately 13.6 ± 3.7 U/g Hb in those without G6PD mutations 1
- For infants more than 30 days old (like this 2-month-old), normal G6PD levels should be around 11.7 ± 3.4 U/g Hb in those without G6PD mutations 1
- Hemizygous males (with G6PD deficiency) over 30 days old typically show levels of 0.9 ± 0.5 U/g Hb 1
Clinical Significance of This Finding
- The measured level of 1.40 U/g Hb is consistent with G6PD deficiency in a male infant of this age 1
- G6PD enzyme activity negatively correlates with age in the first few months of life, which means levels naturally decrease somewhat as infants get older 1
- A G6PD enzyme level below 8.5 IU/g Hb is a significant predictor of severe hyperbilirubinemia in infants 3
Important Considerations
- In the presence of active hemolysis, G6PD levels can be falsely elevated, which may obscure the diagnosis in the newborn period 4
- If G6PD deficiency is suspected despite a borderline level in a hemolyzing neonate, a repeat level should be measured when the infant is 3 months old 4
- The American Academy of Pediatrics recommends performing G6PD testing in infants with significant hyperbilirubinemia, as some may develop a sudden increase in total serum bilirubin 4
Management Implications
- Infants with G6PD deficiency require intervention at lower total serum bilirubin levels than those without deficiency 4
- Close monitoring is essential to prevent kernicterus, a permanent and devastating neurological damage 5
- Education of parents about avoiding triggers of hemolysis is crucial for preventing complications 2
- Phototherapy is an effective treatment for neonatal jaundice in G6PD-deficient infants 2
Potential Complications to Monitor
- Neonatal jaundice that may rapidly escalate to bilirubin-induced neurologic dysfunction 5
- Acute hemolytic anemia when exposed to certain medications, infections, or foods (particularly fava beans) 6
- G6PD-deficient infants are mostly asymptomatic until exposed to oxidative stressors 6
This G6PD level of 1.40 U/g Hb confirms G6PD deficiency in this 2-month-old boy, requiring appropriate monitoring and preventive measures to avoid complications related to this enzyme deficiency.