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Blood Count

G6PD (Glucose-6-Phosphate Dehydrogenase)

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme in red blood cells that helps neutralize oxidative damage. G6PD deficiency is an X-linked genetic disorder, common in India, the Mediterranean, and sub-Saharan Africa. People with deficiency are at risk of sudden hemolysis (red-cell breakdown) when exposed to certain drugs (primaquine, dapsone, sulfa antibiotics, some anti-malarials), infections, or fava beans. Newborns with G6PD deficiency can develop severe jaundice.

Reference Ranges

Male

720.5

U/g Hb

Female

720.5

U/g Hb

Child

720.5

U/g Hb

Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.

What Low Levels Mean

G6PD activity below 7 U/g Hb indicates deficiency. Severity varies — class I is severe (chronic hemolysis), class II–III cause hemolysis only with triggers (most common, including the Indian Mediterranean variant), class IV–V are mild or silent. Affected individuals need a lifelong list of drugs and foods to avoid.

What High Levels Mean

Elevated G6PD is unusual. It may be seen in recent hemolysis with a young red cell population (reticulocytes have high G6PD activity) — this can falsely mask deficiency. If clinical suspicion is strong, repeat the test 2–3 months after the hemolytic episode, when the red cell population has stabilized.

Frequently Asked Questions

Why is G6PD screening important for newborns?

G6PD-deficient newborns can develop severe neonatal jaundice within the first few days of life, leading to kernicterus (permanent brain damage) if not treated. Many Indian states have made universal newborn G6PD screening standard. Early identification allows close jaundice monitoring and avoidance of triggering drugs like naphthalene (mothballs).

What drugs and foods should I avoid with G6PD deficiency?

Avoid primaquine, tafenoquine, dapsone, sulfa antibiotics (cotrimoxazole), nitrofurantoin, methylene blue, rasburicase, and high-dose aspirin. Avoid fava beans (and supplements containing broad beans). Avoid naphthalene (mothballs). Consult a pharmacist before any new medication. Not every drug on the list causes problems in every person — severity varies by variant.

Can women be G6PD deficient?

Yes. Although G6PD deficiency is X-linked and more common in men, women can be affected. Homozygous women (two affected X chromosomes) have the same severity as men. Heterozygous carriers have intermediate enzyme levels and can still experience hemolysis, especially under strong triggers. Family screening is recommended if one member is diagnosed.

This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.

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