G6PD (Glucose-6-Phosphate Dehydrogenase): What Your Result Means

What is G6PD (Glucose-6-Phosphate Dehydrogenase)?

Glucose-6-phosphate dehydrogenase (G6PD) helps red blood cells withstand chemical stress. People with G6PD deficiency — a genetic trait common in people of African, Mediterranean, Middle Eastern, and Southeast Asian ancestry — can suffer sudden red-cell destruction (hemolysis) when exposed to certain triggers. Testing is done when a person has unexplained hemolytic anemia or before starting drugs known to trigger it.

Typical reference interval: Reported as an enzyme activity level compared with a normal reference range (often a percentage or units per gram of hemoglobin). Values below the lab's range indicate deficiency. Testing during or right after a hemolytic episode can falsely read normal, so timing matters.. Laboratories differ — the interval printed on YOUR report always governs.

If your G6PD (Glucose-6-Phosphate Dehydrogenase) is high

Common reasons G6PD (Glucose-6-Phosphate Dehydrogenase) runs above the reference interval:

• Normal enzyme activity — a high-normal G6PD is the expected, healthy result — there is no disease from high G6PD
• Young red blood cells — a hemolytic episode releases young cells with higher enzyme activity, which can transiently raise the measured level

If your G6PD (Glucose-6-Phosphate Dehydrogenase) is low

Common reasons G6PD (Glucose-6-Phosphate Dehydrogenase) runs below the reference interval:

• Inherited G6PD deficiency — the core cause — a genetic variant leaves red cells vulnerable to oxidative stress
• Active hemolysis — during an episode, the most affected cells are destroyed, which can complicate the reading
• Certain medications, fava beans, or infection — these triggers cause hemolysis in deficient people — and can also make the measured level look different
• Newborns — G6PD deficiency is a recognized cause of newborn jaundice

Symptoms worth knowing

Most people with G6PD deficiency have no symptoms at baseline. The danger is triggered: after a drug, fava bean exposure, or infection, red cells break down rapidly, causing jaundice, dark urine, fatigue, and a sharp drop in hemoglobin. Knowing your status prevents the trigger from being a surprise.

What usually happens next

1. A low G6PD result means avoiding known triggers — a clinician provides the specific medication and food list
2. Newborn jaundice or unexplained hemolysis warrants G6PD testing, especially with the relevant ancestry
3. If you have G6PD deficiency, share it with every prescriber — some common drugs (including certain antimalarials and antibiotics) can trigger hemolysis

Frequently asked questions about G6PD (Glucose-6-Phosphate Dehydrogenase) results