Glucose-6-Phosphate Dehydrogenase (G6PD), Quantitative Test
The G6PD, Quantitative test measures the amount of glucose-6-phosphate dehydrogenase enzyme activity in a whole blood sample. It is used to evaluate for G6PD deficiency, a genetic enzyme disorder linked to episodes of red blood cell breakdown and jaundice.
About this test
G6PD is an enzyme, and this quantitative kinetic assay measures how much of it is active in a whole blood sample collected in an EDTA tube. Quest describes it as a way to evaluate for G6PD deficiency, an inherited condition.
Quest lists prolonged newborn jaundice, and in adults episodes of jaundice, dark urine or an enlarged spleen described as acute hemolytic anemia, as situations where this test may be ordered when G6PD deficiency is suspected.
Who might consider this test?
- Often following up on jaundice or a hemolytic episode
- In a newborn or in an adult
- Have a family history that raises the question of G6PD deficiency
Test details
| Quest code | 500 |
|---|---|
| Methodology | Kinetic |
| Sample type | 1 mL whole blood |
| Collection | Quest patient service center |
Reference range
7.0-20.5 U/g Hgb
Reference ranges are general guidance. The range printed on your own laboratory report is the one that applies to your result.
Related tests and panels
Quest resources
Additional details
What this test looks at
The test reports one value: G6PD enzyme activity in whole blood, measured by a kinetic assay and reported as an activity level. Quest lists this test under the aliases G6PD and G6PDH.
How it's often used alongside other tests
Quest notes that molecular testing may be used when enzyme activity comes back normal in heterozygous females, since carriers can have activity levels that overlap with the typical range. A clinician weighs a G6PD result together with the clinical picture, including timing relative to any recent hemolytic episode.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does the G6PD, Quantitative test measure?
It measures the amount of glucose-6-phosphate dehydrogenase (G6PD) enzyme activity in a whole blood sample, using a kinetic assay, and reports the result as an activity level.
How is the sample collected?
The test uses a whole blood sample, collected in an EDTA tube, from a routine blood draw at a Quest Diagnostics patient service center.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Why might this test be ordered?
Quest lists prolonged newborn jaundice, and in adults, episodes of jaundice, dark urine or an enlarged spleen described as acute hemolytic anemia, as situations where G6PD deficiency may be suspected and this test ordered.
Can a normal result rule out G6PD deficiency?
Not always. Quest notes that G6PD levels can appear falsely normal shortly after a hemolytic episode, so a clinician may consider retesting, and molecular testing may be used when activity is normal in heterozygous females.
How much does the Glucose-6-Phosphate Dehydrogenase, Quantitative test cost?
The cash price at Celio Health is $69. That covers the physician's order and sample collection at a Quest patient service center — no insurance is needed and there's no separate doctor's visit to pay for.