Testing.com is fully supported by readers. We may earn a commission through products purchased using links on this page. You can read more about how we make money here.
- Also Known As:
- G-6-PD
- RBC G6PD test
- Formal Name:
- Glucose-6-Phosphate Dehydrogenase

This page was fact checked by our expert Medical Review Board for accuracy and objectivity. Read more about our editorial policy and review process.
-
1
Order Your Test
Online or over the phone
-
2
Find a Lab Near You
Over 3,500 locations to choose from
-
3
Get Your Results
Sent Directly to You
At a Glance
Why Get Tested?
To determine whether you have an inherited G6PD deficiency
When To Get Tested?
When a child experienced persistent jaundice as a newborn for unknown reasons; when you have had one or more intermittent bouts of hemolytic anemia that may be triggered by an infection or certain medications
Sample Required?
A blood sample drawn from a vein in your arm, by fingerstick, or by heelstick (newborns)
Test Preparation Needed?
Generally, none; however, if symptoms are acute, it is advised that you wait to be tested for at least several weeks after the episode has resolved.
You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
What is being tested?
Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme involved in energy production. It is found in all cells, including red blood cells (RBCs) and helps protect them from certain toxic by-products of cellular metabolism. A deficiency in G6PD causes RBCs to become more vulnerable to breaking apart (hemolysis) under certain conditions. This test measures the amount of G6PD in RBCs to help diagnose a deficiency.
G6PD deficiency is a genetic disorder. When individuals who have inherited this condition are exposed to a trigger such as stress, an infection, certain drugs or other substance(s), significant changes occur in the structure of the outer layer (cell membrane) of their red blood cells. Hemoglobin, the life-sustaining, oxygen-transporting protein within RBCs, forms deposits (precipitates) called Heinz bodies. Some individuals may experience these reactions when exposed to fava beans, a condition called “favism.” With these changes, RBCs can break apart more readily, causing a decrease in the number of RBCs. When the body cannot produce sufficient RBCs to replace those destroyed, hemolytic anemia results and the individual may develop jaundice, weakness, fatigue, and/or shortness of breath.
G6PD deficiency is the most common enzyme deficiency in the world, affecting more than 400 million people. It may be seen in up to 10% of African-American males and 20% of African males. It is also commonly found in people from the Mediterranean and Southeast Asia.
G6PD deficiency is inherited, passed from parent to child, due to mutations or changes in the G6PD gene that cause decreased enzyme activity. There are over 440 variants of G6PD deficiency. The G6PD gene is located on the sex-linked X chromosome. Since men have one X and one Y sex chromosome, their single X chromosome carries the G6PD gene. This may result in a G6PD deficiency if a male inherits the single X chromosome with an altered gene.
Since women have two X sex chromosomes, they inherit two copies of the G6PD gene. Women with only one mutated gene (heterozygous) produce enough G6PD that they usually do not experience any symptoms (i.e., asymptomatic), but under situations of stress, they may demonstrate a mild form of the deficiency. In addition, a mother may pass the single mutated gene to any male children. Rarely do women have two mutated gene copies (homozygous), which could result in G6PD deficiency.
G6PD deficiency is a common cause of persistent jaundice in newborns. If left untreated, this can lead to significant brain damage and mental retardation.
Most people with G6PD deficiency can lead fairly normal lives, but there is no specific treatment apart from prevention. They must be cautious and avoid certain medications such as aspirin, phenazopyridine and rasburicase, antibiotics with “sulf” in the name and dapsone, anti-malarial drugs with “quine” in the name, foods such as fava beans, and chemical substances such as naphthalene (found in moth balls). Note that fava beans, often called broad beans, are commonly grown in the Mediterranean area. Acute viral and bacterial infections can also initiate episodes of hemolytic anemia as well as elevated levels of acid in the blood (i.e., acidosis). Individuals should consult with their healthcare practitioner to get a comprehensive list of these triggers. A good starting point is the list found on the G6PD Deficiency Favism Association website.
With hemolytic anemia, RBCs are destroyed at an accelerated rate and the person affected becomes pale and fatigued (anemic) as their capacity for providing oxygen to their body decreases. In severe cases of RBC destruction, jaundice can also be present. Most of these episodes are self-limiting, but if a large number of RBCs are destroyed and the body cannot replace them fast enough, then the affected person may require a blood transfusion. This condition can be fatal if not treated. A small percentage of those affected with G6PD deficiency may experience chronic anemia.
Common Questions
View Sources
Sources Used in Current Review
Reviewed January 2016 by Peter L. Platteborze, PhD, DABCC, FACB, Laboratory Director.
(May 2013 reviewed) KidsHealth.org. G6PD Deficiency. Available online at http://m.kidshealth.org/parent/general/aches/g6pd.html. Accessed on 1/24/2016.
(Reviewed May 2006) Genetics Home Reference: G6PD deficiency. Available online at http://ghr.nlm.nih.gov/condition/glucose-6-phosphate-dehydrogenase-deficiency. Accessed on 1/24/2016.
G6PD Deficiency Information Website. Available online at http://g6pddeficiency.org/wp/#.VqYZbI-cFZV. Accessed on 1/24/2016.
(January 15, 2016 updated). MedlinePlus Medical Encyclopedia: G6PD Deficiency. Available online at https://www.nlm.nih.gov/medlineplus/g6pddeficiency.html. Accessed on 1/24/2016.
National Newborn Screening and Genetics Resource Center. Available online at http://genes-r-us.uthscsa.edu/. Accessed on 1/24/2016.
(November 3, 2014 updated) G6PD Deficiency Favism Association. Available online at http://www.g6pd.org/en/G6PDDeficiency/SafeUnsafe/DaEvitare_ISS-it. Accessed on 1/24/2016.
GTR: the Genetic Test Registry – G6PD. Available online at http://www.ncbi.nlm.nih.gov/gtr/conditions/C0017758/. Accessed on 1/24/2016.
Platteborze PL, Matos R, Gidvany-Diaz V, Wilhelms KW. An Unexpected Emergency Request for Glucose-6-Phosphate Dehydrogenase Testing in a 9-Year-Old African American Boy. Lab Medicine 2015: 46(2): 150-152.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO. Pp 449-450.
(© 2004). Glucose-6-Phosphate Dehydrogenase. ARUP’s Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.aruplab.com/guides/clt/tests/clt_a266.jsp#1149592.
Pradell, L. (2003 January, Reviewed). G6PD deficiency. KidsHealth, Nemours Foundation [On-line information]. Available online at http://kidshealth.org/parent/general/aches/g6pd.html.
Lica, L. (©2001 – 2004). Glucose-6-phosphate dehydrogenase deficiency. Blueprint for Health, Blue Cross and Blue Shield of Minnesota [On-line information]. Available online at http://blueprint.bluecrossmn.com/article/gale/100084627.
Dhaliwal, G. et. al. (2004 June 1). Hemolytic Anemia. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20040601/2599.html.
Cutler, C. (2003 September 14, Updated). Glucose-6-phosphate dehydrogenase deficiency. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000528.htm.
Cutler, C. (2003 August 18, Updated). Hemolytic crisis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003270.htm.
Elstrom, R. (2001 October 25, Reviewed). Glucose-6-phosphate dehydrogenase deficiency. University of Maryland Medicine [On-line information]. Available online at http://www.umm.edu/ency/article/000528.htm.
(© 2004). Newborn Screening Tests. March of Dimes [On-line information]. Available online at http://www.modimes.org/pnhec/298_834.asp.
WHO Working Group, Beutler, E. et. al. (1989). Glucose-6-phosphate dehydrogenase deficiency [64 paragraphs]. Bulletin of the World Health Organization 67 (6): 601-611. [On-line journal]. PDF available for download at http://whqlibdoc.who.int/bulletin/1989/Vol67-No6/bulletin_1989_67(6)_601-611.pdf.
Beutler, E. (© 1996-2004). Erythrocyte disorders: Anemias due to increased destruction of erythrocytes with enzyme deficiencies Glucose-6-phosphate dehydrogenase deficiency. G6PD Deficiency favism association [On-line article from Williams’ HEMATOLOGY]. Available online at http://www.rialto.com/favism/english/index.mv?pgid=beutler_01.
The Ness Foundation: What is Oxidative Stress? Available online at http://www.ness-foundation.org.uk/What-is-Oxidative-Stress.html.
Netdoctor.co.uk. Oxidative Stress. Available online at http://www.netdoctor.co.uk/focus/nutrition/facts/oxidative_stress/oxidativestress.htm.
Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby’s Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 497-498.
Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 456-457.
Ben-Joseph, E. (2006 August, Reviewed). G6PD deficiency. Nemours Foundation, KidsHealth for Parents [On-line information]. Available online at http://kidshealth.org/parent/general/aches/g6pd.html. Accessed on 8-27-08.
Matsui, W. (2007 February 26, Updated). Glucose-6-phosphate dehydrogenase deficiency. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000528.htm. Accessed on 8-27-08.
Henningson, C. (2007 March 22, Updated). Glucose-6-phosphate dehydrogenase. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003671.htm. Accessed on 8-27-08.
(2006 May, Reviewed). Glucose-6-phosphate dehydrogenase deficiency. Genetics Home Reference [On-line information]. Available online at http://ghr.nlm.nih.gov/condition=glucose6phosphatedehydrogenasedeficiency. Accessed on 8-27-08.
(2006 September). What is Hemolytic Anemia. NHLBI [On-line information]. Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/ha/ha_whatis.html. Accessed on 8-27-08.
G6PD Deficiency Favism Association, What is G6PD Deficiency? Available online at http://www.g6pd.org/favism/english/index.mv?pgid=intro. Accessed September 2008.
Wintrobe’s Clinical Hematology. 12th ed. Greer J, Foerster J, Rodgers G, Paraskevas F, Glader B, Arber D, Means R, eds. Philadelphia, PA: Lippincott Williams & Wilkins: 2009. Pp 933-939.
Gersten T. (Updated 2012 February 8). Glucose-6-phosphate dehydrogenase. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003671.htm. Accessed June 2012.
(© 1995-2012). Test ID: G6PD8368 Glucose-6-Phosphate Dehydrogenase (G-6-PD), Quantitative, Erythrocytes. Mayo Clinic May Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8368. Accessed June 2012.
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency. Merck Manual for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed June 2012.
Cook, J. et. al. (Updated 2011 July). Hemolytic Anemias. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/HemolyticAnemias.html?client_ID=LTD#tabs=0. Accessed June 2012.
Dugdale, D. (Updated 2010 March 28). Glucose-6-phosphate dehydrogenase deficiency. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000528.htm. Accessed June 2012.
(Updated 11 December 19). National Newborn Screening Status Report. National Newborn Screening and Genetics Resource Center [On-line information]. Available online at http://genes-r-us.uthscsa.edu/nbsdisorders.htm. Accessed June 2012.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 502-503.
Elghetany MT, Banki K (2011): Erythrocytic disorders, in Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22ed. McPherson RA, Pincus MR, eds. Elsevier Saunders. Pp 557-600.
Ask a Laboratory Scientist
