What is GLUCOSE 6 PHOSPHATE DEHYDROGENASE G6PD QUANTITATIVE test?

Also Known As: G6PD test, G6PDD test, G6PD deficiency test

The levels of the G6PD enzyme are measured in blood by GLUCOSE 6 PHOSPHATE DEHYDROGENASE G6PD QUANTITATIVE test. Before going into details of the test, it’s necessary to know what the G6PD enzyme is and what function it plays in the cell.

 Our blood is a medium where oxygen, hormones, dissolved gases, and nutrients are present and transported through the body. These constituents are transported by different cells and structures.

Cells need many enzymes and proteins to maintain their structure and function. The enzyme named glucose 6 phosphate dehydrogenase G6PD is necessary for the normal function of Red blood cells.

Red blood cells carry oxygen via a protein called hemoglobin and transfer the oxygenated blood to various body parts. RBCs need oxygen to grow, reproduce and function normally. Glucose 6 phosphate dehydrogenase G6PD maintains normal cell growth, making it carry oxygen to different parts of the body.

Red blood cells function abnormally when the G6PD enzyme is deficient. This usually happens in a genetic disorder, an X-linked recessive trait more likely to affect males. When your body doesn’t have the G6PD gene on the X chromosome, it will destroy RBCs leading to a condition called hemolytic anemia. In hemolytic anemia, cells don’t get enough oxygen to survive and function normally.

What is the test used for?

 A G6PD test is done to check the G6PD levels in the blood. The symptoms of hemolytic anemia may vary in different people, but if you have any of these symptoms, your doctor might recommend the G6PD test:

• Fatigue
• Tachycardia
• Dyspnea
• Splenomegaly
• Anemia
• Jaundice

Moreover, many people don’t get symptoms until they are exposed to triggers like;

• Bacterial or Viral infections
• Anti-Malarial medications
• Medications like NSAIDs
• Antibiotics, etc

The test is run after the doctor has ruled out the other causes of anemia.

 Why and when do you need a G6PD test?

 Suppose you are facing the symptoms like yellowing of skin and sclera of eyes, Tiredness, weight loss, muscle fatigue, low hemoglobin levels, Fast heartbeat, etc. In that case, you need to get this test done after the doctor’s prescription.

 What kind of sample is required for the test?

For G6PD deficiency, you need to give a blood sample to run the tests to confirm it. The phlebotomist draws a blood sample from one of your veins and collects it in a vial. You get a stinging sensation, but it goes away soon. The blood sample is then stored in the vial and processed later.

Do you need to prepare for the test?

Yes, you must follow a few preparatory steps to give a blood sample for the G6PD test because some medications can interfere with the results. If you are on drugs or nutritional supplements, let your doctor know. They advise you to stop the medicines before giving blood for the test sample.

Test results can be false if you eat fava beans or take sulfa drugs. Sulfa drugs include diuretics, antibiotics, anti-fungal, and anticonvulsant drugs. Other than that, it is unnecessary to fast or not eat and drink before giving the blood sample. But testing can be delayed if you are experiencing a hemolytic episode.

After giving the sample, your blood is safely put into the blood vial and sent to the laboratory to run the test. Your doctor will discuss the test reports with you. Low levels of G6PD indicate the deficiency of the enzyme and gene on the X chromosome, thus the indication of inherited disease; hemolytic anemia.

There is no cure for this disorder other than you can prevent the symptoms by avoiding specific triggers. Few painkillers and dietary supplements might be its trigger. You should know what to avoid.

Are there any risks to this test?

There is no risk to this test other than if you have a needle phobia and refrain from giving blood samples. Tell your laboratory technologist about it; they keep fine needles and cannulas for this purpose.

 What do the test results mean?

The reference range for normal G6PD levels is 6.75-11.95U/g Hb for adults; for neonates, normal levels are 10.15-14.71 U/g Hb. Suppose test results indicate the G6PD levels below as compared to the reference range. In that case, if there is a deficiency of G6PD in your blood, it means you have a genetic disorder, i.e., hemolytic anemia. Your RBCs are not functional enough to deliver oxygen to the body. This can lead to the symptoms of hemolytic anemia. Though, the reference range might differ with different reagents.

Related Tests:

• Bilirubin Blood Test
• Complete Blood Count (CBC)
• Hemoglobin Test