Lab test

Glucose 6-Phosphate Dehydrogenase (G6PD) Test, Quantitative

The glucose-6-phosphate dehydrogenase (G6PD) quantitative test measures the activity of the G6PD enzyme in red blood cells.

Typical price

From $158

Results

1-3 business days

Preparation

See preparation notes below

Sample

Blood draw or sample collection at a local center

The glucose-6-phosphate dehydrogenase (G6PD) quantitative test measures the activity of the G6PD enzyme in red blood cells. G6PD helps protect red blood cells from oxidative stress, and low activity can make cells more vulnerable to breakdown, leading to hemolytic anemia under certain triggers such as infections, fava beans, or some medications. The quantitative test reports the level of enzyme activity rather than simply detecting its presence. It is used to evaluate suspected deficiency and to guide monitoring. Results are interpreted by a healthcare provider in the context of symptoms and timing.

• Glucose-6-phosphate dehydrogenase (G6PD) activity The measured activity of the G6PD enzyme in red blood cells; low activity is associated with G6PD deficiency.

• People with a family history of G6PD deficiency or hemolytic anemia
• Individuals with ancestry from regions where G6PD deficiency is more common
• People who develop anemia after an infection, fava beans, or certain medications
• Those being evaluated after an episode of red blood cell breakdown
• Anyone whose healthcare provider recommends testing before using a medication that can trigger hemolysis

• No fasting is required for this test
• A standard blood draw is used to collect the sample
• Tell the lab about any recent blood transfusion, which can affect G6PD activity results
• Testing soon after an acute hemolytic episode can give misleading results, so a healthcare provider may recommend timing the sample carefully

A low G6PD activity level may indicate G6PD deficiency, which can make red blood cells more vulnerable to breakdown when exposed to certain triggers. A normal result generally suggests adequate enzyme activity, but testing during or soon after an episode of hemolysis can falsely suggest normal activity because the most affected cells may have already been cleared. This is why timing matters and why results are interpreted with your clinical picture. Discuss your G6PD result with a healthcare provider before making any decisions.

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