Glucose-6-Phosphate Dehydrogenase, Quant.

The Glucose-6-Phosphate Dehydrogenase, Quant. test contains 1 test with 1 biomarker.

Description: The Glucose 6 Phosphate Dehydrogenase, or G6PD, test is used to determine if you inherited a G6PD deficiency.

Also Known As: G6PD Test, G6PD Enzyme Test, RBC G6PD test, G-6-P-D Test

Collection Method: Blood Draw

Specimen Type: Whole Blood

Test Preparation: No preparation required

Average Processing Time: 4 to 5 days

When is a Glucose-6-Phosphate Dehydrogenase test ordered?

When a person develops signs and symptoms of hemolytic anemia, G6PD enzyme testing is done. When someone has experienced an episode of elevated RBC destruction but the crisis has passed, testing may be done.

When other lab test findings point to hemolytic anemia, testing may be performed. 

When alternative causes of anemia and jaundice have been eliminated and several weeks have passed since an acute episode, G6PD activity testing is usually recommended.

If available, newborn screening can be done in the first day or two after birth.

What does a Glucose-6-Phosphate Dehydrogenase blood test check for?

The enzyme glucose-6-phosphate dehydrogenase is involved in the creation of energy. It is found in all cells, including red blood cells, and aids in the protection of these cells against some hazardous by-products of cellular metabolism. RBCs with a G6PD deficit are more susceptible to splitting apart under specific situations. To assist diagnose a deficit, this test analyzes the quantity of G6PD in RBCs.

G6PD insufficiency is a hereditary condition. When people who have inherited this illness are exposed to a trigger like stress, infection, certain medicines, or another substance, the structure of their red blood cells changes significantly. Heinz bodies are deposits formed by hemoglobin, the life-sustaining, oxygen-transporting protein found in RBCs. When exposed to fava beans, some people have these symptoms, which is known as "favism." RBCs might break apart more easily as a result of these alterations, resulting in a reduction in the quantity of RBCs. Hemolytic anemia occurs when the body is unable to manufacture enough RBCs to replace those that have been destroyed. Symptoms include jaundice, weakness, exhaustion, and/or shortness of breath.

G6PD insufficiency is the most common enzyme deficiency, affecting over 400 million individuals worldwide. It can be found in as many as 10% of African-American men and 20% of African men. People from the Mediterranean and Southeast Asia are also susceptible.

Due to mutations or alterations in the G6PD gene that produce lower enzyme activity, G6PD deficiency is inherited and handed down from parent to kid. G6PD insufficiency has approximately 440 different forms. The G6PD gene is found on the X chromosome, which is inherited from both parents. Because men have only one X and one Y chromosome, the G6PD gene is only found on the X chromosome. If a guy gets the single X chromosome with a mutated gene, he may have G6PD deficiency.

Women inherit two copies of the G6PD gene since they have two X chromosomes. Women with only one mutant gene produce enough G6PD to show no symptoms most of the time, although they may show a minor version of the deficit in stressful settings. A mother can also carry the single altered gene to any male children she has. Women with two defective gene copies, which could lead to G6PD deficiency, are uncommon.

In infants, G6PD deficiency is a prevalent cause of chronic jaundice. This can result in substantial brain damage and mental impairment if left untreated.

The majority of persons with G6PD deficiency can live relatively normal lives, however there is no specific treatment for it other than prevention. They must be cautious and avoid pharmaceuticals like aspirin, phenazopyridine, and rasburicase, as well as antibiotics with "sulf" in the name and dapsone, anti-malarial treatments with "quine" in the name, foods like fava beans, and chemical chemicals like naphthalene. Fava beans, often known as broad beans, are widely farmed in the Mediterranean region. Acute viral and bacterial infections can cause hemolytic anemia and blood acid levels to rise. Individuals should seek a thorough list of these triggers from their healthcare provider. The list on the G6PD Deficiency Favism Association website is a nice place to start.

RBCs are destroyed at a faster rate in hemolytic anemia, and the person affected feels pale and tired as their ability to provide oxygen to their body decreases. Jaundice can be observed in severe cases of RBC breakdown. The majority of these episodes are self-limiting, but if a substantial number of RBCs are lost and the body is unable to replenish them quickly enough, the affected person may require a blood transfusion. If not addressed, this illness can be fatal. Chronic anemia can afflict a small number of people with G6PD deficiency.

Lab tests often ordered with a Glucose-6-Phosphate Dehydrogenase test:

  • Complete Blood Count (CBC)
  • Reticulocyte Count
  • Bilirubin
  • Hemoglobin
  • Red Blood Cell Count
  • Lactate Dehydrogenase (LD)
  • Haptoglobin

Conditions where a Glucose-6-Phosphate Dehydrogenase test is recommended:

  • Hemolytic Anemia

How does my health care provider use a Glucose-6-Phosphate Dehydrogenase test?

The enzyme assay for glucose-6-phosphate dehydrogenase is used to screen for and diagnose G6PD deficiency. It could be used to screen children who were born with unexplained chronic jaundice. Currently, babies are not routinely tested for G6PD deficiency; however, this depends on the state that offers the service. According to the National Newborn Screening and Genetics Resource Center, two states, Pennsylvania and the District of Columbia, offer G6PD testing as part of their newborn screening panel as of November 2014.

G6PD is an enzyme present in all cells, including red blood cells, that protects them against hazardous by-products of cellular metabolism. RBCs with a G6PD deficit are more susceptible to splitting apart under specific situations.

People of any age who have experienced unexplained episodes of hemolytic anemia, jaundice, or dark urine may benefit from G6PD testing to assist establish a diagnosis. G6PD deficiency may be suspected if the person had a recent viral or bacterial illness or was exposed to a recognized trigger, followed by a hemolytic event.

G6PD testing may be repeated on occasion to validate initial findings. A simple qualitative test is usually used in screening tests to determine if a person has a high amount of G6PD in his or her cells. A quantitative test will be used to determine the actual quantity of enzyme activity during confirmation testing.

G6PD levels are normal in newly generated cells in the most prevalent form of G6PD deficiency seen in people of African heritage, but decline by up to 75% as RBCs age. As a result, testing should be delayed for several weeks after a hemolytic episode has passed. The older, more fragile G6PD-deficient RBCs are often killed during the episode, leaving the newer, less deficient cells to be tested, potentially hiding a G6PD deficiency.

Although genetic testing is not commonly performed, it can be requested as a follow-up to an enzyme test that suggests a deficiency in order to discover which G6PD mutations are present. There are currently around 440 G6PD gene variants that can produce varied degrees of deficiency based on the mutation and the specific person. Some mutations have no effect on the activity of the G6PD enzyme. The G6PD mutations have been divided into five groups by the World Health Organization, depending on the enzyme levels and their influence on the affected person's health. During testing, however, only the most prevalent G6PD mutations are discovered. If a certain mutation is known to exist in a family line, tests to detect that mutation can be performed.

What do my Glucose-6-Phosphate Dehydrogenase test results mean?

A deficit is indicated by a low level of G6PD enzyme. When exposed to a trigger, an affected person is more likely to develop symptoms. However, the findings cannot be utilized to forecast how an affected individual will react in a specific situation. Symptom severity varies from person to person and from episode to episode.

If a male has a normal G6PD enzyme level, he is unlikely to have a deficit, and if anemia is present, it is most likely due to another cause. If the test was done during a bout of hemolytic anemia, it should be redone several weeks later once the RBC population has replenished and matured.

Carriers, who have one mutant and one normal gene copy, will have some G6PD-deficient RBCs and others that are not. G6PD levels in these women are normally normal or near normal, and they rarely exhibit symptoms. A carrier will have a normal or low normal G6PD level, therefore they may not be discovered by G6PD screening, but they will be detected by a G6PD confirmation test, which measures the overall quantity of enzyme present in the cells. It's worth noting that a rare female with two defective gene copies will almost certainly have a large drop in G6PD levels.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: G-6-PD (B), Glucose 6 Phosphate, Glucose6Phosphate Dehydrogenase Quant


A blood glucose test measures the amount of a sugar called glucose in a sample of your blood. Glucose is a major source of energy for most cells of the body, including those in the brain. The hormones insulin and glucagon help control blood glucose levels.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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