G6PD Test:
G6PD (Glucose-6-phosphate dehydrogenase) is an enzyme involved in energy production which helps red blood cells function normally and protects them from toxic substances. Deficiency of this enzyme makes RBCs vulnerable and susceptible to hemolysis (breakdown of RBCs) under certain conditions. G6PD test measures the amount of this enzyme in the blood to diagnose if there is a deficiency.
Factors involved to understand the normal range of G6PD levels:
- What is the normal range of G6PD?
- What do low G6PD levels mean?
- Symptoms of G6PD deficiency
- Causes of G6PD Deficiency
- Precautions to be taken to maintain a normal G6PD level
- Are there any risk factors associated with this test?
- What other tests are ordered along with G6PD test?
What is the normal range of G6PD?
The normal range of G6PD test is 8.8-13.4U/g Hb.
Reference values have not been established for patients who are <12 months of age.
What do low G6PD levels mean?
Lower than normal levels of G6PD enzyme indicates a deficiency. G6PD protects the erythrocytes against reactive oxygen species. The deficiency can leave the RBCs vulnerable to toxic substances and may lead to their premature and rapid destruction resulting in hemolytic anemia. Low levels of G6PD in blood also lead to neonatal hyperbilirubinemia.
Symptoms of G6PD deficiency
Most patients with G6PD deficiency don’t experience any symptoms. In some cases, people with the deficiency can experience symptoms on exposure to certain medications, food, or infections that may cause premature and rapid destruction of RBCs.
Common symptoms of G6PD deficiency include:
- Rapid heart rate
- Shortness of breath
- Dark or yellow-orange coloured urine
- Fever
- Fatigue and dizziness
- Paleness
- Jaundice or yellowing of skin
- Pain in the abdomen or back
- Sudden rise in body temperature
- Enlarged spleen
- Gastrointestinal problems such as diarrhoea, nausea, etc.
G6PD deficiency can cause persistent neonatal jaundice and is one of the most common medical problem in newborns.
Causes of G6PD Deficiency
G6PD deficiency is a genetic disorder that occurs in males and females but is commonly found in males. It is caused due to a mutation in the G6PD gene that leads to decreased enzyme activity. The condition is triggered when affected individuals are exposed to triggers such as stress, infection, fava beans, certain medications such as anti-malarial drugs, etc. These factors lead to an increase in the levels of reactive oxygen species, causing rapid destruction of red blood cells.
Other potential triggers of this condition are naphthalene, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDS), certain medications used to treat UTIs, some pain killers, etc.
Precautions to be taken to maintain a normal G6PD level
To manage G6PD deficiency, avoiding food and medications that may trigger the condition is often advised. Foods such as fava beans and some legumes, medications such as anti-malarial drugs, aspirin, antibiotics with sulfonamides, anti-inflammatory drugs, etc. can trigger the deficiency and hence, must be avoided. Reducing stress levels may also help in managing the symptoms of the condition.
Are there any risk factors associated with this test?
A G6PD test is a simple blood test that rarely leads to any side effects. There are, however, certain minor risks associated with this test. These include heamatoma, excessive bleeding, swelling at the area from where the blood was drawn, fainting, infection at the site of puncture, etc. These side effects rarely cause any complications and usually resolve on their own.
There are no complicated or major risks involved with the test.
What other tests are ordered along with G6PD test?
Along with a G6PD test, several other diagnostic tests are generally ordered to confirm the deficiency and cause of hemolytic anemia. These tests include a complete blood count (CBC) test, serum hemoglobin test, and a reticulocyte count test. Results of these tests provide information about the RBCs in the body and help in the diagnosis of hemolytic anemia. In addition, genetic testing can be performed to confirm the diagnosis.
Follow-up appointments to discuss test results are often recommended.
G6PD test is ordered to determine the exact causes of hemolytic anemia. This test is often ordered after the doctor has ruled out all the other causes of anemia and persistent jaundice. It is also done to confirm the results obtained from other blood tests such as a CBC test and to monitor the progress of ongoing treatments. Abnormal results can point towards a G6PD deficiency.
No special preparation is required for this test. However, it is important to let your health care provider know about your diet, if you have recently consumed fava beans, taken sulfa drugs such as diuretics, or any other over-the-counter medications. You may be advised to stop them as they can interfere with the test results.
