Your Red Blood Cell Defense Enzyme
G6PD is an enzyme that protects red blood cells from oxidative damage. It generates NADPH, which is the antioxidant shield for RBCs. Without enough G6PD, certain medications, foods (fava beans), or infections cause oxidative stress that destroys red blood cells—hemolytic anemia. It's the most common enzyme deficiency worldwide, affecting ~400 million people.
What is G6PD (Glucose-6-Phosphate Dehydrogenase)?
G6PD is the rate-limiting enzyme in the pentose phosphate pathway, generating NADPH for glutathione reduction (antioxidant defense in RBCs). X-linked recessive: primarily affects males. ~400 million people worldwide are deficient. Testing during acute hemolysis may be falsely normal (deficient cells already destroyed).
↑ What High G6PD (Glucose-6-Phosphate Dehydrogenase) Means
Not clinically significant.
Common symptoms:
Not applicable
↓ What Low G6PD (Glucose-6-Phosphate Dehydrogenase) Means
G6PD deficiency—your red blood cells are vulnerable to oxidative stress. Triggers (medications, fava beans, infection) can cause sudden, severe hemolytic anemia. X-linked inheritance: primarily affects males. Very common in Mediterranean, African, and Asian populations.
Common symptoms:
During hemolytic crisis: sudden anemia, fatigue, pallor, jaundice, dark urine · Back pain (from massive hemolysis) · Shortness of breath, tachycardia · Between crises: completely asymptomatic
Why It Matters
When normal:
Identifies susceptibility to drug-induced hemolysis
Prevents life-threatening hemolytic crises
Guides medication safety (avoid oxidant drugs)
One-time test (genetic condition)
Risks if abnormal:
Deficient: hemolytic crisis with oxidant exposure
Medications to avoid: primaquine, dapsone, rasburicase, methylene blue, sulfonamides, nitrofurantoin
Fava beans can trigger severe hemolysis ("favism")
What Can Cause Abnormal Levels?
Genetic (X-linked)
100% likelyInherited enzyme deficiency. Over 400 genetic variants identified. Severity varies by variant.
Testing Timing
Testing during acute hemolysis gives falsely normal results (deficient cells already hemolyzed). Retest 2-3 months after acute episode.
What You Can Do
AVOID oxidant medications: primaquine, dapsone, rasburicase, nitrofurantoin, sulfonamides
Impact: Prevents hemolytic crisis \u00B7 Timeline: Lifelong
Avoid fava beans (broad beans) if severe deficiency
Impact: Fava beans contain oxidants that trigger hemolysis \u00B7 Timeline: Lifelong
Carry medical alert identification
Impact: Ensures healthcare providers know to avoid oxidant drugs \u00B7 Timeline: Always
If lifestyle changes aren't enough:
If hemolytic crisis occurs: supportive care, hydration, transfusion if severe
Impact: Most episodes are self-limited once trigger is removed \u00B7 Timeline: Acute
Recommended retest: One-time genetic test (but retest if drawn during acute hemolysis)
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