G6PD Test: Detecting Enzyme Deficiency and Avoiding Triggers

What Is the G6PD Test?

The Glucose 6 phosphate dehydrogenase( G6PD) test is a diagnostic blood test that measures the activity of glucose-6-phosphate dehydrogenase (G6PD), an essential enzyme in red blood cells. This enzyme helps protect the cells from oxidative damage, which can lead to their premature destruction, a condition known as haemolysis and cause heamolytic anaemia.

The G6PD blood test is crucial for identifying G6PD deficiency, a genetic disorder that affects millions worldwide. Individuals with this red blood cell disorder have reduced G6PD enzyme activity, making their red blood cells more vulnerable to damage from certain triggers like infections, medications, and foods.

By measuring G6PD levels, the test helps diagnose the deficiency, allowing the doctors  to guide patients in avoiding triggers and managing their condition effectively.

Why Is the G6PD Test Recommended?

The G6PD test is recommended in several situations:

• Unexplained haemolytic anaemia: If a person experiences symptoms of anaemia where the blood haemoglobin is low, such as fatigue, shortness of breath, and pale skin, without a clear cause, a G6PD test can help determine if the anaemia is due to G6PD blood deficiency.
• Family history: G6PD deficiency is an inherited disorder. If a family member has been diagnosed with the condition, it's advisable to get tested.
• High-risk ethnic groups: G6PD deficiency is more common in certain ethnic groups, particularly those from Africa, the Middle East, and Southeast Asia. People from these backgrounds may consider testing.
• Before starting certain medications: Some drugs, like antimalarials and antibiotics, can trigger haemolysis in G6PD-deficient individuals. Testing may be recommended before starting such treatments.
• Newborn screening: In some countries, the G6PD test is part of routine newborn screening to identify the deficiency early and prevent complications.

How Is the G6PD Test Performed?

The G6PD levels procedure involves the following steps:

• A phlebotomist will clean the skin over a vein in your arm with an antiseptic.
• A small needle is inserted into the vein, and a blood sample is collected into a vial or syringe.
• The blood sample is sent to a laboratory for analysis, where the G6PD enzyme activity is measured.

G6PD Test Results: Normal vs. Deficient Levels

G6PD test results are typically reported as enzyme activity levels in units per gram of haemoglobin (U/g Hb). The normal range may vary slightly between laboratories but is generally as follows:

• Normal G6PD levels: 5-15 U/g Hb
• Mild deficiency: 2-7 U/g Hb
• Severe deficiency: Less than 2 U/g Hb[1][3]

Results below the normal range of G6PD levels indicate a deficiency, with lower levels suggesting a more severe deficiency. It's important to note that false-negative results can occur if the test is performed during or shortly after a haemolytic episode, as the older, deficient red blood cells may have been destroyed, leaving only younger cells with higher enzyme activity.

What happens during a G6PD test for a baby?

Newborn G6PD testing is typically performed using a small blood sample obtained from a heel prick, a procedure known as a newborn blood spot or dried blood spot test.

Here's what happens during the G6PD test:

• A phlebotomist/healthcare provider warms the baby's heel to increase blood flow.
• The heel is cleaned with an antiseptic wipe and gently pricked with a small lancet.
• A few drops of blood are collected on a special filter paper card.
• The card is allowed to dry and then sent to a laboratory for analysis.
• The laboratory measures the G6PD enzyme activity in the dried blood spot.

This simple procedure is usually performed within the first few days of life, along with other newborn screening tests.

How do I prepare for a G6PD test?

Generally, no special preparation is needed for a G6PD test. You can eat and drink normally before the test, and most medications can be continued as usual.

However, it's important to inform your healthcare provider about:

• Any symptoms you're experiencing, such as fatigue, shortness of breath, or yellowing of the skin or eyes
• Your family history of G6PD deficiency or other blood disorders
• All medications, supplements, and herbal remedies you're taking, as some may affect test results

In some cases, your healthcare provider may ask you to stop taking certain medications temporarily before the test to ensure accurate results.

What are the risks of a G6PD test?

The G6PD blood test is a safe and routine procedure with minimal risks. However, as with any blood test, some minor side effects may occur:

• Pain or discomfort: You may feel a brief sting when the needle is inserted into your vein. Some people experience mild pain or throbbing at the needle site after the test.
• Bruising: A small bruise may develop at the needle site. This is more likely if you have a bleeding disorder or are taking blood-thinning medications.
• Bleeding: Rarely, the vein may continue to bleed after the needle is removed. Applying pressure to the site for several minutes usually stops this.

These side effects are usually mild and short-lived. Serious complications from a G6PD test are extremely rare. If you experience persistent pain, swelling, or signs of infection at the needle site, contact your healthcare provider promptly.

Conclusion: Should You Get Tested for G6PD Deficiency?

If you have symptoms of haemolytic anaemia, a family history of G6PD deficiency, or belong to a high-risk ethnic group, getting a G6PD blood test is a smart choice. Early diagnosis of this common red blood cell disorder can help you avoid triggers and prevent serious complications.

At Metropolis Healthcare, we understand the importance of accurate and timely diagnostic testing. Our team of skilled phlebotomists can perform at-home sample collection for your convenience, and our state-of-the-art laboratories ensure reliable G6PD test results.

FAQs

What if G6PD is high?

Elevated G6PD levels are uncommon and generally not a cause for concern.

• In some cases, high levels may be due to a rare variant of G6PD deficiency or a temporary increase in enzyme activity following a haemolytic episode.
• If your G6PD is unexpectedly high, your healthcare provider may recommend retesting or further evaluation.

What is the G6PD normal range?
The reference range for G6PD levels is typically between 5 and 15 units per gram of haemoglobin (U/g Hb). However, this range may vary slightly between laboratories. Your Doctor will interpret your G6PD test results based on the specific range used by the testing laboratory.

Is G6PD deficiency common?

Yes, G6PD blood deficiency is the most common enzymatic disorder of red blood cells, affecting an estimated 400 million people worldwide. The prevalence varies among ethnic groups, with higher rates in regions where malaria is or was common, such as Africa, the Middle East, and Southeast Asia.

Can a G6PD deficiency lead to serious health problems?

While most people with G6PD deficiency don't experience symptoms, exposure to certain triggers can lead to serious complications:

• Haemolytic anaemia: Rapid destruction of red blood cells, causing fatigue, shortness of breath, and jaundice
• Neonatal jaundice: Severe jaundice in newborns, which can lead to brain damage if untreated
• Acute kidney failure: Rarely, severe haemolysis can cause kidney damage

What is considered a low G6PD level?

G6PD levels below the reference range of 5-15 U/g Hb are considered low. Mild deficiency is typically characterized by levels between 2-7 U/g Hb, while levels below 2 U/g Hb suggest a more severe deficiency. The lower the enzyme activity, the greater the risk of haemolysis when exposed to triggers.

Can G6PD patients live a normal life?

Yes, with proper management, people with G6PD deficiency can lead normal, healthy lives. The key is to avoid known triggers, such as certain medications, foods (like fava beans), and chemicals. Regular check-ups with a healthcare provider can help monitor for signs of haemolysis and ensure appropriate care.

Is fasting required for the G6PD test?

No, fasting is not necessary before a G6PD test. You can eat and drink normally prior to the blood draw. However, it's important to inform your healthcare provider about any medications or supplements you're taking, as some may affect test results.

Who should get tested for G6PD deficiency?

G6PD testing is recommended for:

• Newborns, as part of routine screening in some countries
• People with unexplained haemolytic anaemia or jaundice
• Individuals with a family history of G6PD deficiency
• Those belonging to high-risk ethnic groups, such as African, Middle Eastern, or Asian descent
• People before starting certain medications, like antimalarials or sulfa drugs

Can G6PD deficiency be cured?

Currently, there is no cure for G6PD deficiency. It is a genetic condition that cannot be corrected. However, the disorder can be effectively managed by avoiding triggers and receiving prompt treatment for haemolytic episodes. With proper care, most people with G6PD deficiency can enjoy a normal lifespan and quality of life.

How long does it take to get G6PD test results?

The turnaround time for G6PD test results varies depending on the laboratory and testing method used. Typically, results are available within a few hours after the blood sample is collected.