Glucose-6 Phosphate Dehydrogenase (G6PD), Quantitative Test
Glucose-6 Phosphate Dehydrogenase (G6PD), Quantitative
G6PD is the abbreviation of an enzyme, glucose-6-phosphate dehydrogenase, that helps in the proper functioning of red blood cells (RBCs). RBCs transport oxygen from the lungs to all the cells of the body for optimal health, growth, and reproduction.
This test measures the amount of glucose-6-phosphate dehydrogenase present in the blood. Its deficiency leads to a condition called G6PD deficiency, which is a genetic disorder mostly affecting males. A genetic mutation in the G6PD gene leads to the breakdown of RBCs. This condition, where the body destroys RBCs at a faster rate than it can replace them, is called hemolytic anemia. People with this deficiency show symptoms only when they are exposed to certain “triggers,” including broad beans, bacterial and viral infections, and anti-malaria medicines.
G6PD test is also known as G6PD deficiency test, G-6-PD, RBC G6PD test, glucose-6-phosphate dehydrogenase test.
Glucose-6 phosphate dehydrogenase is an important component of the pentose phosphate pathway (PPP) and is Involved in the generation of nicotinamide adenine dinucleotide phosphate (NADPH). It also helps in the proper working of RBCs and protects them from free radicals called reactive oxygen species (ROS)
Symptoms of G6DP deficiency (Hemolytic anemia)
Fainting
Fatigue
Increased heartbeat
Shortness of breath
Skin and eyes turning yellow (Jaundice)
Dark or yellowish colored urine
Who should get tested?
The following should get tested for G6PD:
Babies born with jaundice that persists for two weeks
Babies with a family history of G6PD deficiency
Test preparation:
No special preparation is required for this test. In this test, a fine needle is inserted into a vein in your arm to draw out a blood sample, which is collected in a test tube or vial. In the case of infants, blood is drawn from the heel of the baby.
Interpretation of results
The World Health Organization (WHO) has classified 4 categories of phenotypes associated with G6PD deficiency.
|
WHO classification |
Clinical presentation |
G6PD activity |
|
I |
Chronic non-spherocytic hemolytic anemia (CNSHA) |
<10% |
|
II |
Asymptomatic unless triggered |
<10% |
|
III |
Asymptomatic unless triggered |
10%-60% |
|
IV |
None |
Normal |
Except for individuals with CNSHA, those with G6PD deficiency do not show any symptoms (asymptomatic) unless faced with a “trigger” such as broad beans, bacterial or viral infections, or anti-malaria drugs.
It’s these triggering factors that can lead to acute hemolytic anemia (AHA) in individuals with G6PD deficiency. If a G6PD genetic mutation is detected in a person, he is most likely to exhibit some of the symptoms associated with G6PD deficiency, to varying degrees. Thus, it is important to avoid triggers that can lead to hemolytic anemia
FAQs
What precautions should I take before undergoing a G6PD test?
There are no such major precautions required to be taken before taking the test. A person about to take the G6PD test does not need to stop eating or drinking (fasting) before the test. However, certain foods such as broad beans and medications (sulfa drugs) such as antibacterial medicines, anti-malaria drugs, etc. should be avoided right before the test is taken. These are potential triggers for hemolytic anemia. Please inform your healthcare provider prior about the medicines or foods you take and follow their instructions closely
Does a G6PD deficiency result in a serious condition?
Many people with G6PD deficiency do not show any symptoms of hemolytic anemia and can carry on with their normal activities without any hindrances. However, people prone to hemolytic anemia should always avoid “triggers.” In some cases, the symptoms of hemolytic anemia become severe and require immediate medical attention
Are women unaffected by G6PD deficiency?
Women with slightly lower levels of G6PD may be “carriers” of G6DP deficiency. This means that they have one normal G6PD gene and one defective G6PD gene. Such females rarely show any symptoms as their normal G6PD gene is capable of producing enough RBCs. However, there is a possibility of passing on the defective gene to their offspring
Which test is recommended along with a G6PD test?
If you are on a medication that triggers mild or moderate G6PD deficiency, your healthcare provider might put you on a low dose of the “trigger” medication. In such cases, a complete blood count test is required as a monitoring test along with the G6PD test
Name some of the “triggers” that can cause hemolytic anemia
Triggers such as broad beans, bacterial and viral infections, and anti-malarial drugs can cause hemolytic anemia in an individual. Non-steroidal anti-inflammatory drugs (NSAIDs) should also be avoided by a person prone to an attack of hemolytic anemia
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