Glucose 6-Phosphate Dehydrogenase (G6PD) Test
This page explains the glucose 6-phosphate dehydrogenase (g6pd) test, what it measures, and how to arrange it. The Glucose 6-Phosphate Dehydrogenase (G6PD) test measures the amount of an enzyme called G6PD in red blood cells. This enzyme helps protect red blood cells from damage. The test is ordered to check for G6PD deficiency, a condition that can cause red blood cells to break down too early (hemolysis) when exposed to certain triggers.
- Sample type
- blood
- Category
- Metabolic & Glucose
- Turnaround
- 1-3 business days
- Price
- $158
- Referral
- Not required
The Glucose 6-Phosphate Dehydrogenase (G6PD) test measures the amount of an enzyme called G6PD in red blood cells. This enzyme helps protect red blood cells from damage. The test is ordered to check for G6PD deficiency, a condition that can cause red blood cells to break down too early (hemolysis) when exposed to certain triggers.
What it measures
- G6PD enzyme activity — The main measurement. It shows how well the enzyme is working in your red blood cells.
- Hemoglobin — The protein in red blood cells that carries oxygen. Low levels can be a sign of anemia.
- Reticulocyte count — The number of young red blood cells. A high count may mean your body is making more red blood cells to replace those being destroyed.
- Bilirubin — A yellow substance made when red blood cells break down. High levels can cause jaundice (yellowing of the skin and eyes).
Who it is for
A healthcare provider may order this test if you have symptoms of hemolysis, such as jaundice, dark urine, or fatigue, especially after taking certain medications or eating fava beans. It is also used to screen people before starting drugs that can trigger hemolysis, or if you have a family history of G6PD deficiency.
Preparation
No special preparation is needed for this test. You do not need to fast. Tell your provider about any medications or supplements you take, as some can affect the results.
Results and what they mean
Results are usually reported as a number that shows your G6PD enzyme activity level. A low level suggests G6PD deficiency, but your clinician will interpret the result along with your symptoms and other tests. This information is not medical advice; only a qualified healthcare provider can diagnose a condition and recommend treatment.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the glucose 6-phosphate dehydrogenase (g6pd) test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
No, fasting is not required. You can eat and drink normally before the test.
What does a low G6PD result mean?
A low result may indicate G6PD deficiency, which means your red blood cells are more easily damaged. Your provider will discuss what this means for you.
Can I have this test if I already had a blood transfusion?
A recent blood transfusion can affect the results. Tell your provider if you have had a transfusion recently, as you may need to wait before testing.
Is G6PD deficiency serious?
Most people with G6PD deficiency live normal lives by avoiding certain triggers, such as specific medications, fava beans, and infections. Your provider can give you personalized guidance.