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Glucose-6-Phosphate Dehydrogenase Phenotype by Red Blood Cell Indirect Method

Published: August 9, 2026Updated: August 17, 2026

This test helps determine your red blood cells' ability to produce an enzyme called glucose-6-phosphate dehydrogenase (G6PD), which is important for protecting cells from oxidative stress.

Quick summary

["G6PD levels can affect how you respond to certain medications or infections."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
42319-4
Short code
G6PD Phenotyp RBC-Imp
Synonyms
G6PD Phenotyp RBC-Imp
Category
glucose
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test if you have symptoms like anemia, jaundice (yellow skin), or if you’re taking medications that can trigger a rare but serious condition called hemolytic anemia (destruction of red blood cells). It’s also used to screen for G6PD deficiency, which can make you more sensitive to certain foods, drugs, or infections.

What Does the Test Involve?

A small blood sample is taken from your arm. The test measures how your red blood cells react to an oxidizing agent, which helps identify your G6PD enzyme activity level.

What Are the Results Meaningful For?

Results help confirm whether you have a low or normal G6PD activity, which can guide decisions about medications, dietary precautions, or monitoring for potential reactions to certain substances.

How Long Does It Take to Get Results?

Results are typically available within 24 to 48 hours, depending on lab processing times.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

G6PD Phenotyping (RBC)

Frequently asked questions

What does a low G6PD result mean?
A low result suggests you may have G6PD deficiency, which can make you more prone to hemolytic anemia if exposed to certain triggers. Your doctor will discuss safe medications, foods, and monitoring with you.
Can G6PD deficiency be treated?
There’s no direct cure for G6PD deficiency, but managing triggers—like avoiding certain medications or foods—can help prevent symptoms. Hydration and rest may also support your body during episodes.
Does this test require fasting?
No fasting is needed for this test, as it only involves a blood sample.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy