Is a Glucose-6-Phosphate Dehydrogenase (G6PD) level of 1.40 considered normal in a 2-month-old male infant?

Normal G6PD Level for a 2-Month-Old Male Infant

A G6PD level of 1.40 U/g Hb is normal for a 2-month-old male infant. This value falls within the expected reference range for infants of this age with normal G6PD enzyme activity.

Reference Ranges for G6PD in Infants

• For male infants under 30 days of age, the G6PD enzyme activity levels in hemizygotes (those with G6PD deficiency) average 1.4 ± 0.9 U/g Hb, while normal infants without G6PD mutations have levels of 13.6 ± 3.7 U/g Hb 1
• For male infants more than 30 days old, G6PD enzyme activity levels in hemizygotes average 0.9 ± 0.5 U/g Hb, while those without G6PD mutations have levels of 11.7 ± 3.4 U/g Hb 1
• G6PD enzyme activity is negatively correlated with age in infants (R = -0.212, p = 0.01) 1

Interpretation of G6PD Results

• A G6PD level of 1.40 U/g Hb in a 2-month-old male infant is consistent with hemizygous G6PD deficiency 1
• G6PD deficiency is the most common enzyme disorder globally and an important cause of neonatal jaundice 2
• The diagnosis of G6PD deficiency is typically made when enzyme activity is less than 8.5 IU/g Hb, which is a significant predictor of severe hyperbilirubinemia 3

Clinical Implications

• G6PD deficiency can lead to life-threatening hemolytic crises when exposed to specific drugs, fava beans, or during infections 4, 2
• In newborns, G6PD deficiency increases the risk of hyperbilirubinemia that may rapidly escalate to bilirubin-induced neurologic dysfunction (BIND) 5
• 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 (TSB) 6

Monitoring and Management

• Infants with G6PD deficiency require intervention at lower TSB levels than those without deficiency 6
• Close monitoring is essential to prevent kernicterus, a permanent and devastating neurological damage 5
• The World Health Organization recommends screening for G6PD activity in all infants in countries with high prevalence of this deficiency 2

Important Considerations

• G6PD deficiency in the neonatal period often presents without overt signs of hemolysis, making laboratory confirmation crucial 5
• In the presence of hemolysis, G6PD levels can be elevated, which may obscure the diagnosis in the newborn period 6
• If G6PD deficiency is strongly suspected despite a normal level in a hemolyzing neonate, a repeat level should be measured when the infant is 3 months old 6

Prevention of Complications

• Complications of G6PD deficiency can largely be prevented through education and information 2
• Parents should be educated about avoiding triggers that can cause hemolysis in G6PD-deficient infants 2
• Neonatal jaundice in G6PD-deficient infants can be successfully treated with phototherapy 2