Platform
Company
Immunology & Autoimmune
Review status
Currently under review
Pending specialist review and validation.
The G6PD quantitative test measures how active the enzyme glucose-6-phosphate dehydrogenase is in your red blood cells. This enzyme helps protect red blood cells from everyday oxidative stress by supporting the cell’s natural antioxidant systems.
Doctors use this test to check for inherited G6PD deficiency, a common condition that can make red blood cells more fragile under certain stresses. It may be ordered if you have symptoms of hemolysis, unexplained anemia or jaundice, a family history of the condition, or before you are given specific medicines that require screening.
If G6PD activity is low, you may be at higher risk of sudden breakdown of red blood cells when exposed to particular triggers, such as certain medicines, infections, or fava beans. Knowing your G6PD status helps you and your care team prevent avoidable episodes of hemolysis by steering clear of high-risk exposures and by planning safe treatments.
Clinicians also use this test in newborns with jaundice, in people with ancestry from regions where the condition is more common, and before prescribing some antimalarial drugs or agents like rasburicase. Identifying deficiency supports tailored care, counseling for family members when appropriate, and safer medication choices over a lifetime.
If your result shows reduced enzyme activity, it suggests G6PD deficiency. Your clinician will review your history, provide a list of medicines and substances to avoid, and may recommend confirming the result when you are well and not in the middle of a hemolytic episode. Some people, especially females, can have intermediate results due to genetic mosaicism, which may prompt repeat testing or genetic testing for clarification.
A result in the normal range makes significant deficiency unlikely, but results can be misleading soon after a hemolytic event or after a transfusion. In those situations, retesting at a later time may be advised. Regardless of the number, talk with your clinician about what the result means for your medications, travel plans, and steps to take if you develop symptoms of hemolysis.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Transfused donor red blood cells can temporarily mask a true deficiency, making activity appear higher than your own baseline. If possible, testing is best performed after transfused cells have cleared.
Right after a hemolytic episode, you may have more young red blood cells, which can show higher enzyme activity and give a false sense of normal. Repeat testing after recovery can provide a truer picture.
Certain drugs and chemicals can trigger hemolysis in people with deficiency, including some antibiotics, antimalarials, rasburicase, methylene blue, and naphthalene, as well as fava beans. Always check with your clinician or pharmacist.
G6PD is an enzyme, so delayed processing or exposure of the sample to heat can reduce measured activity. Proper collection and prompt laboratory handling help ensure accurate results.
G6PD deficiency is inherited in an X-linked pattern. Females can have intermediate results because of mixed cell populations, which may require confirmatory or genetic testing for clear interpretation.
Newborn red blood cells can show different enzyme activity patterns, and pregnancy introduces physiological changes. Results in these settings are interpreted alongside clinical context and may warrant follow-up testing.
References