G6PD Test Explained: Normal Range, Deficiency, Triggers & Report Reading (India 2026) | G6PD डेफिशिएंसी टेस्ट गाइड

G6PD Deficiency Test Explained: Normal Range, Triggers, Haemolytic Crisis & Report Reading (India 2026)

G6PD डेफिशिएंसी टेस्ट गाइड: नॉर्मल रेंज, ट्रिगर्स — दवाएं, खाना और संक्रमण, और हेमोलाइटिक एनीमिया

A plain-language guide for patients & families · भारतीय मरीज़ों के लिए सरल मार्गदर्शिका

Your child was given the antimalarial drug primaquine and suddenly developed severe anaemia, dark urine, and jaundice. Or your newborn has unexplained neonatal jaundice. Or your doctor found an abnormally low CBC result and suspects haemolytic anaemia. G6PD deficiency is one of the most common inherited enzyme deficiency conditions in India, affecting an estimated 10–15% of certain tribal and community populations — yet most affected individuals never know they have it until they receive a specific triggering drug or food. This guide explains G6PD testing, what deficient means, and — most critically — which drugs and foods must be avoided for life.

If your doctor also ordered a CBC alongside, see that guide too. For reading lab reports generally, see our beginner's guide to blood test reports.

G6PD डेफिशिएंसी भारत में सबसे आम वंशानुगत एंजाइम कमियों में से एक है। अधिकांश प्रभावित व्यक्तियों को तब तक पता नहीं चलता जब तक कोई दवा या खाना हेमोलाइटिक क्राइसिस नहीं उत्पन्न करता।

 Table of Contents / विषय सूची

1. What Is G6PD? / G6PD क्या है?
2. Normal Range, Test Types & WHO Classification
3. Triggers — Drugs, Foods & Infections to Avoid
4. Symptoms of Haemolytic Crisis / लक्षण
5. G6PD Deficiency in India — Prevalence & Malaria
6. Reading Your Report
7. Test Preparation Checklist
8. Frequently Asked Questions / FAQ

Image 1: G6PD (Glucose-6-Phosphate Dehydrogenase) is an enzyme present in every red blood cell. Its sole function: to produce NADPH — the molecule that regenerates glutathione, the cell's primary antioxidant defence. When red blood cells are exposed to oxidative stress (from certain drugs, fava beans, or infection), G6PD-normal cells produce sufficient NADPH to neutralise the free radicals. G6PD-deficient cells cannot produce enough NADPH → glutathione is depleted → oxidative stress overwhelms the cell → Heinz bodies form on haemoglobin → red blood cell membrane ruptures (haemolysis). The cell is destroyed in the spleen. This causes haemolytic anaemia — the hallmark of G6PD deficiency crises.

500M+ people worldwide carry G6PD deficiency — making it the most common enzymopathy globally. In India, prevalence ranges from 2–10% in general population to 10–15% in certain tribal and malaria-endemic communities.

X-linked G6PD deficiency is X-linked recessive — boys/men are more severely affected; girls/women are usually carriers with milder or no disease. A boy has only one X chromosome; one defective copy = full deficiency.

Preventable Every haemolytic crisis in G6PD deficiency is preventable by avoiding specific drugs, foods, and infections. There is no cure — but there is complete disease control through avoidance of known triggers. The trigger list is lifelong.

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What Is G6PD? / G6PD क्या है?

G6PD (Glucose-6-Phosphate Dehydrogenase) is an enzyme present in every red blood cell. It is the first step of the pentose phosphate pathway — a metabolic route that produces NADPH (Nicotinamide Adenine Dinucleotide Phosphate). NADPH is essential for regenerating glutathione — the cell's primary defence against oxidative damage. Red blood cells are uniquely vulnerable to oxidative stress because they carry oxygen (which generates reactive oxygen species) and — unlike other body cells — have no mitochondria or nucleus, so the pentose phosphate pathway is the only source of NADPH protection. When G6PD enzyme activity is reduced (by gene mutations on the X chromosome), RBCs cannot generate adequate NADPH → glutathione is depleted → oxidative stress destroys red cell membranes → haemolysis (red cell rupture) → haemolytic anaemia.

G6PD एंजाइम लाल रक्त कोशिकाओं को ऑक्सीडेटिव क्षति से बचाता है। G6PD कमी → NADPH कम → Glutathione कम → ऑक्सीडेटिव तनाव → Red cell rupture → हेमोलाइटिक एनीमिया।

Why G6PD deficiency persists — the malaria protection paradox:

• G6PD deficiency has been maintained at high frequency in malaria-endemic regions (Sub-Saharan Africa, Middle East, South Asia — including India) because heterozygous carrier females have a survival advantage against malaria.
• When P. falciparum infects a G6PD-heterozygous red cell, it encounters an environment with reduced glutathione → the malaria parasite cannot complete its life cycle as efficiently → the infected cell is phagocytosed by the spleen before the parasite replicates → relative protection against severe malaria.
• This is why G6PD deficiency is most prevalent in exactly the same geographic areas where malaria is (or was historically) most endemic — including large parts of India.
• The G6PD gene mutation is the same evolutionary mechanism as sickle cell trait and thalassaemia trait — both also provide malaria protection.

Evolutionary paradox: G6PD कमी मलेरिया-स्थानिक क्षेत्रों में उच्च आवृत्ति पर बनी रहती है क्योंकि heterozygous carrier महिलाओं को मलेरिया से सापेक्ष सुरक्षा मिलती है। Sickle cell और thalassaemia trait के समान।

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Normal Range, Test Types & WHO Classification

G6PD testing can be qualitative (deficient vs normal) or quantitative (enzyme activity level). Most Indian labs offer both:

G6PD परीक्षण qualitative (deficient या normal) या quantitative (enzyme activity) हो सकता है।

Test Type	Method	Normal Result	Deficiency Result	Best Use
G6PD Qualitative (Fluorescence Spot Test)	NADPH fluoresces under UV light — absent/reduced fluorescence = deficiency	"Normal" or "Adequate"	"Deficient" or "No fluorescence"	Newborn screening; rapid screening; most cost-effective (₹200–400)
G6PD Quantitative (Enzyme Activity Assay)	Spectrophotometric measurement of NADPH production rate	7–20 U/g Hb (range varies by lab/platform)	<7 U/g Hb (deficient) <30% of normal = severe	Confirm diagnosis; WHO classification; carrier detection; monitoring post-haemolytic episode
G6PD Genotyping (Molecular)	PCR/sequencing identifies specific gene mutations	No pathogenic variant detected	Specific mutation identified (G202A, A376G — common Indian variants)	Definitive diagnosis; carrier detection in women; family counselling (₹2,000–5,000)

WHO Class	Enzyme Activity	Clinical Severity	Indian Relevance
Class I	<1% of normal	Chronic non-spherocytic haemolytic anaemia — haemolysis even without triggers	Very rare in India
Class II	1–10% of normal	Severe — acute haemolysis with mild triggers; neonatal jaundice	G6PD Mediterranean — common in some Indian communities
Class III (most common)	10–60% of normal	Moderate — acute haemolytic anaemia with significant triggers only	G6PD A- variant common in India; asymptomatic without exposure
Class IV & V	60–150%+ of normal	No clinical disease — normal or increased activity	Normal — no clinical significance

⚠️ Critical testing caveat — false normal during haemolytic crisis: The G6PD enzyme activity level can appear falsely normal during an active haemolytic episode. This paradox occurs because: during haemolysis, the oldest red cells (which have the lowest G6PD activity) are preferentially destroyed first. The remaining circulating red cells are younger (reticulocytes) — which have higher G6PD activity even in a deficient patient. This can make a G6PD-deficient patient's enzyme level appear near-normal or borderline. Always test G6PD activity 3–4 weeks AFTER resolution of a haemolytic crisis for accurate results. If clinical suspicion is high and the result is borderline after a crisis, retest or proceed to molecular genotyping. हेमोलाइटिक crisis के दौरान G6PD activity falsely normal दिख सकती है — पुरानी G6PD-low cells पहले नष्ट होती हैं, reticulocytes में activity अधिक। Crisis के 3–4 सप्ताह बाद परीक्षण करें।

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Triggers — Drugs, Foods & Infections to Avoid

Image 2: G6PD deficiency triggers — drugs, foods, and infections that must be avoided lifelong. Key drug triggers in India: Primaquine (antimalarial — the most important in India; required for P. vivax radical cure but CONTRAINDICATED in G6PD deficiency); Dapsone (leprosy, PCP prophylaxis — widely used in India); Nitrofurantoin (UTI treatment — very common in India); Ciprofloxacin at high doses; certain sulphonamides. Food triggers: Fava beans (broad beans/bakla — cause the most dramatic haemolytic crises). Infections themselves are a major trigger — viral and bacterial infections cause oxidative stress independently of drugs.

 AVOID THESE DRUGS — High-Risk Triggers in India ये दवाएं AVOID करें — उच्च जोखिम

• Primaquine — antimalarial for P. vivax radical cure and P. falciparum gametocyte clearance. Most important drug to avoid in India. G6PD testing is mandatory before prescribing primaquine.
• Tafenoquine — newer anti-relapse antimalarial; same risk as primaquine
• Dapsone — leprosy treatment, PCP prophylaxis; widely used across India
• Nitrofurantoin — oral UTI antibiotic; very commonly prescribed in India
• Methylene blue — used for methaemoglobinaemia — CANNOT be given in G6PD deficiency (paradoxically worsens haemolysis)
• Rasburicase — hyperuricaemia in tumour lysis; contraindicated
• High-dose aspirin and high-dose Vitamin C (above 1g/day)

⚠️ USE WITH CAUTION — Intermediate-Risk Drugs सावधानी से उपयोग करें

These drugs carry lower risk and can usually be used in Class III (mild-moderate) G6PD deficiency at standard doses, but require monitoring in Class II (severe) deficiency:

• Chloroquine — antimalarial; generally safe at standard doses but use with caution
• Quinine — for malaria treatment; generally safe at therapeutic doses
• Trimethoprim-Sulfamethoxazole (Co-trimoxazole) — common antibiotic; generally safe in mild G6PD deficiency
• Ciprofloxacin — at standard doses; avoid high doses
• Probenecid
• Always consult haematologist before prescribing any sulphonamide, antimalarial, or antibiotic in a known G6PD-deficient patient

Fava beans (Broad Beans / Bakla) Fava beans — खाना निषिद्ध

Fava beans (Vicia faba — called bakla in some Indian regions, broad beans) contain vicine and convicine — powerful oxidants that directly trigger haemolytic crises in G6PD-deficient individuals even without any drug exposure. The condition is called favism. A haemolytic crisis from fava beans can develop within hours of eating them and can be severe enough to require blood transfusion. Important: fava beans are different from French beans, green beans, rajma, or dal — these are safe. Fava beans are a flat, broad, pale green bean. They are not commonly consumed in most of India but are used in some communities. G6PD-deficient individuals should strictly avoid fava beans for life.

Infections — independent trigger संक्रमण — स्वतंत्र ट्रिगर

Viral and bacterial infections are a major trigger for haemolytic crises in G6PD-deficient individuals — independently of any drug. The infection triggers haemolysis through oxidative stress generated by the inflammatory response (activated neutrophils release hydrogen peroxide and superoxides that damage G6PD-deficient red cells). In India, this is especially important: Dengue fever, malaria itself, hepatitis A and E, typhoid, and even severe influenza can all trigger haemolytic anaemia in G6PD-deficient individuals — sometimes making the diagnosis (G6PD deficiency) apparent only during the infectious illness. Early fever management and prompt treatment of infections is essential in G6PD-deficient patients.

The Primaquine-G6PD problem — why this is the most critical issue in Indian malaria management:

• P. vivax malaria requires primaquine for radical cure (to eliminate liver hypnozoites that cause relapses). Without primaquine, P. vivax relapses every few months indefinitely.
• Primaquine is an absolute contraindication in G6PD deficiency — it causes severe acute haemolytic anaemia.
• India has both: very high P. vivax malaria burden AND high G6PD deficiency prevalence in the same communities (Odisha, Chhattisgarh, Jharkhand, Madhya Pradesh, tribal areas).
• NVBDCP (National Vector Borne Disease Control Programme) mandates G6PD testing before primaquine prescription. In practice, this is not consistently followed — causing preventable primaquine-induced haemolytic crises across India.
• If G6PD testing is unavailable: primaquine is either withheld (accepting malaria relapse risk) or given at a lower dose under close monitoring. Tafenoquine (newer drug) also requires G6PD testing.

P. vivax malaria: Primaquine जरूरी है — लेकिन G6PD कमी में पूर्णतः contraindicated। NVBDCP: Primaquine से पहले G6PD test अनिवार्य। व्यवहार में: अक्सर follow नहीं होता — preventable crises।

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Symptoms of Haemolytic Crisis / हेमोलाइटिक क्राइसिस के लक्षण

Image 3: G6PD deficiency haemolytic crisis symptoms. Most G6PD-deficient individuals are completely asymptomatic at baseline — the condition only manifests when triggered. The haemolytic crisis typically begins 24–72 hours after trigger exposure. Key warning signs: sudden onset severe fatigue and weakness; pallor (pale skin and conjunctivae); jaundice (yellow eyes and skin — from bilirubin released by haemolysed red cells); dark tea- or cola-coloured urine (haemoglobinuria — free haemoglobin from ruptured red cells passing into urine); abdominal or back pain; rapid heart rate; breathlessness. Neonates: prolonged jaundice — particularly from Days 2–7. In severe crises: haemoglobin may fall from 12 g/dL to 5–6 g/dL within days, requiring blood transfusion.

Acute haemolytic crisis symptoms — appear 24–72 hours after trigger तीव्र हेमोलाइटिक क्राइसिस

• Dark urine (tea/cola/Coca-Cola coloured) — the most alarming and specific symptom; haemoglobinuria from massive red cell destruction
• Jaundice — yellow eyes and skin, appearing within 24–48 hours of trigger; bilirubin rising from haemolysed cells
• Severe sudden fatigue — patient collapses; breathlessness even at rest
• Pallor — profound anaemia; haemoglobin may fall by 4–6 g/dL in 24–48 hours
• Abdominal and back pain — from red cell lysis products and spleen engorgement
• Fever — from trigger infection or haemolytic response
• Laboratory: very low haemoglobin, elevated bilirubin, elevated LDH, elevated reticulocytes, bite cells/blister cells on peripheral smear, Heinz bodies

Neonatal jaundice from G6PD deficiency नवजात पीलिया

G6PD deficiency is an important cause of neonatal jaundice in India — particularly in G6PD-endemic regions. Key features that suggest G6PD as the cause: jaundice appearing on Day 2–7 (not first 24 hours); male neonates predominantly; family history of neonatal jaundice or G6PD deficiency; no ABO/Rh blood group incompatibility; jaundice persisting or worsening beyond Day 5; may require phototherapy or exchange transfusion. G6PD-related neonatal jaundice in India is often triggered by: traditional remedies (some camphor/naphthalene products used in Indian households are G6PD triggers — keep infants away); herbal medicines given by traditional practitioners; henna (mehendi) applied to skin — can absorb through neonatal skin and trigger haemolysis. Every male neonate with unexplained significant jaundice in India should have G6PD tested.

Self-limiting nature — the crisis resolves स्वयं-सीमित

An important reassurance for G6PD-deficient patients: most acute haemolytic crises in Class III (mild-moderate) deficiency are self-limiting. When the trigger is removed (stop the offending drug, recover from infection), haemolysis stops. The bone marrow responds with a reticulocytosis (burst of new red cell production) → haemoglobin recovers over 2–3 weeks. Blood transfusion is required only for severe crises (Hb falls below 6–7 g/dL with symptoms). Class II deficiency crises are more severe and may require hospitalisation and transfusion. No specific treatment for G6PD deficiency exists beyond trigger avoidance — supportive care during crises, folic acid supplementation during recovery to support marrow recovery.

CBC findings during G6PD haemolytic crisis CBC निष्कर्ष

The CBC during a haemolytic crisis shows:

• Low haemoglobin — may fall precipitously (e.g., 12 → 6 g/dL in 48 hours)
• High reticulocyte count — bone marrow response to haemolysis
• Elevated MCV — reticulocytes are larger than mature red cells
• Peripheral smear: Bite cells (semicircular notches from Heinz body removal by spleen), blister cells, polychromasia (young reticulocytes)
• Elevated bilirubin (indirect/unconjugated — from haemoglobin breakdown)
• Elevated LDH — released from lysed red cells
• Low haptoglobin — bound to free haemoglobin released by haemolysis
• Haemoglobinuria on urine test (brown/red urine)

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G6PD Deficiency in India — Prevalence & Regional Distribution

High-prevalence communities in India भारत में उच्च-प्रसार समुदाय

G6PD deficiency prevalence in India varies significantly by region and community. Highest prevalence: Tribal populations — Gond, Bhil, Korku, Munda, Oraon in Odisha, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra (10–20% in some communities); Parsi community (Zoroastrians) — particularly high prevalence; Scheduled Castes and Tribes in malaria-endemic belts; Muslim communities in some regions. Most common Indian G6PD variants: G6PD Mediterranean (Class II) — more severe; common in some South Indian and Muslim communities; G6PD A- variant (Class III) — milder; more common in tribal populations.

Neonatal screening — why India needs it नवजात screening की जरूरत

India does not yet have a national newborn screening programme for G6PD deficiency, unlike many developed countries and some middle-income countries. This means: G6PD-deficient neonates are exposed to triggers without anyone knowing they are at risk; neonatal G6PD jaundice is misattributed to ABO incompatibility or physiological jaundice; G6PD-deficient children receive primaquine or nitrofurantoin without prior testing. Several Indian states — Goa, some ICMR programmes — have piloted G6PD neonatal screening. The qualitative fluorescent spot test costs less than ₹150 per newborn. Universal neonatal G6PD screening in malaria-endemic states would prevent thousands of haemolytic crises annually.

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Reading Your Report

Report Result	What It Means	Gender Significance	Action
G6PD: NORMAL / ADEQUATE (Qualitative) OR enzyme activity within normal range (Quantitative)	No G6PD Deficiency G6PD enzyme activity sufficient to protect red cells from oxidative stress.	Normal for males and females	No restriction on drugs or foods. Can receive primaquine normally. No further G6PD testing needed.
G6PD: DEFICIENT (Qualitative) OR enzyme activity below 7 U/g Hb (Quantitative)	G6PD Deficiency Confirmed Significantly reduced enzyme activity — risk of haemolytic crisis on exposure to triggers.	Males: hemizygous (one X chromosome) — full deficiency Females: homozygous — full deficiency (rare)	Lifelong trigger avoidance list. No primaquine without specialist supervision. Carry a G6PD deficiency card. Screen first-degree relatives. Genetic counselling if planning family.
G6PD: INTERMEDIATE / BORDERLINE (Quantitative — enzyme 30–70% of normal)	Partial Deficiency / Carrier State Often heterozygous females — mosaicism of normal and deficient cells.	Females predominantly — heterozygous carriers have intermediate activity	Avoid Class I/II triggers (primaquine, dapsone, fava beans). Standard drugs usually safe. Genetic counselling. Sons have 50% risk of deficiency.

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Test Preparation Checklist / टेस्ट की तैयारी

G6PD testing requires specific preparation to avoid falsely normal results:

G6PD परीक्षण के लिए falsely normal results से बचने के लिए विशिष्ट तैयारी आवश्यक है।

• ✓
  Test at least 3–4 weeks AFTER recovery from a haemolytic episode. This is the single most important preparation rule. During and immediately after a haemolytic crisis, the oldest (most deficient) red cells are destroyed — the remaining younger red cells (reticulocytes) have higher G6PD activity, making the result falsely normal. Always wait 3–4 weeks after full recovery, when the blood is back to steady-state composition, for an accurate result.
• ✓
  Test at least 3 months after a blood transfusion. Transfused donor red cells carry the donor's G6PD activity (which is normal). After transfusion, the result will reflect the donor's normal enzyme activity — masking the patient's actual deficiency. Wait at least 3 months (one red cell lifespan) after any blood transfusion before testing G6PD.
• ✓
  No fasting required. G6PD is an enzyme activity test on red blood cells — food intake does not affect red cell enzyme levels. You can eat and drink normally before the test.
• ✓
  Disclose all recent medications. Some drugs (like dapsone and primaquine) cause selective destruction of G6PD-deficient cells — if tested while still taking these, the result may appear falsely normal for the same reason as during crisis (deficient cells preferentially destroyed). Stop suspected triggering medications before testing if possible and clinically safe to do so.
• ✓
  For females — qualitative test may miss heterozygous carriers. The qualitative fluorescent spot test is not reliable for detecting G6PD carrier women — heterozygous females have one normal and one deficient X chromosome; their intermediate enzyme activity may appear "normal" on qualitative screening. For accurate carrier detection in females: quantitative G6PD enzyme assay or molecular genotyping is required. This is especially important in family counselling and preconception screening.
• ✓
  Proper blood sample handling. G6PD enzyme activity degrades with time and temperature. The sample must be processed within 24 hours at 2–8°C or within 6 hours at room temperature. Do not let the sample sit in heat (no leaving in car or hot environment). Use an NABL-accredited lab that handles enzyme assays correctly.

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✅ Book G6PD Test + CBC — Home Collection Available

Always book G6PD (qualitative + quantitative if deficient on qualitative) together with CBC. Order only when in steady state — NOT during or within 3–4 weeks of a haemolytic episode or within 3 months of a blood transfusion:

G6PD Enzyme Activity (Quantitative) + G6PD Qualitative Screen + CBC G6PD enzyme assay + fluorescent spot test + CBC with peripheral smear · NABL-accredited lab · No fasting required · Must be in steady state (3–4 weeks post-crisis, 3 months post-transfusion) · Home collection · Digital report · Available across India

Book G6PD Test →

Affiliate link: I may earn a small commission at no extra cost to you. G6PD testing is available at government hospitals and medical colleges across India, particularly in malaria-endemic states. If you or your child is in an active haemolytic crisis (dark urine, sudden severe pallor, jaundice after drug exposure) — go directly to the hospital emergency department.

G6PD testing सरकारी अस्पतालों और medical colleges में उपलब्ध। Active haemolytic crisis (गहरा मूत्र, अचानक पीलापन, पीलिया) पर सीधे hospital emergency जाएं।

 Home Monitoring & Emergency Preparedness for G6PD Families

For families with G6PD-deficient members — particularly children — two essential tools: a digital thermometer (fever from infection is a G6PD haemolysis trigger; monitoring temperature enables early action) and a well-stocked first aid kit (helps manage minor crises before reaching hospital). A haemolytic crisis with dark urine, jaundice, or severe pallor always requires immediate hospital care — these are supportive tools, not treatment.

Dr Trust (USA) Waterproof Flexible Tip Digital Thermometer — 604

For G6PD-deficient individuals — particularly children — fever monitoring is critically important because infections are a major independent trigger for haemolytic crises. Early detection of fever allows prompt treatment of the underlying infection before it precipitates significant haemolysis. The earlier the infection is treated, the lesser the oxidative stress burden on G6PD-deficient red cells. A fever above 38.5°C in a G6PD-deficient child warrants immediate medical attention — both to treat the infection AND to watch for early signs of haemolysis (dark urine, rapid pallor). If dark urine develops alongside fever — this is a haemolytic crisis. Go to hospital immediately.

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HomeStrap First Aid Kit Bag — Medicine Storage Box

A well-organised first aid kit and medicine storage box is essential for families with G6PD-deficient members — particularly for safely storing the G6PD-SAFE medication list (paracetamol for fever, oral rehydration salts, G6PD deficiency medical ID card) and ensuring that UNSAFE medications (primaquine, dapsone, nitrofurantoin) are never inadvertently given during an illness. Every G6PD-deficient individual and their family should carry: (1) a written G6PD deficiency card listing safe and unsafe medications; (2) paracetamol (the safest fever reducer in G6PD deficiency); (3) ORS sachets for hydration during febrile illness. This kit provides organised storage to keep all medications labelled and accessible in emergencies. A G6PD-deficient person should NEVER take a new medication without first verifying it is G6PD-safe with their haematologist or doctor.

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Know a family with G6PD deficiency who needs guidance on triggers, drugs to avoid, and what the test means? Share this guide. क्या आप किसी ऐसे परिवार को जानते हैं जिन्हें G6PD डेफिशिएंसी है? ट्रिगर्स और दवाओं के बारे में यह गाइड शेयर करें।

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Related Tests / संबंधित जांचें

These tests are commonly ordered alongside G6PD in the anaemia workup:

G6PD के साथ ये जांचें अक्सर करवाई जाती हैं:

CBC (Complete Blood Count) Serum Iron & Ferritin LFT (Bilirubin) Malaria Antigen Test Vitamin B12 Test How to Read a Blood Test Report

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Frequently Asked Questions / अक्सर पूछे जाने वाले सवाल

What is the normal G6PD level in India?

G6PD is reported in two ways: Qualitative (Normal/Deficient) and Quantitative (enzyme activity in U/g Hb). For the quantitative assay, normal activity at most Indian NABL labs is 7–20 U/g Hb (reference ranges vary by assay platform — always check your lab's specific range). Below 7 U/g Hb is considered deficient. Below 30% of normal activity (approximately below 2–6 U/g Hb depending on platform) = severe deficiency (WHO Class II or above). For the qualitative fluorescent spot test, the result is simply "Normal" (fluorescence present) or "Deficient" (no/reduced fluorescence). This qualitative test is reliable for males and homozygous females but may miss heterozygous female carriers who require quantitative testing.

उत्तर: Quantitative: Normal 7–20 U/g Hb। Deficient: <7 U/g Hb। Qualitative: Normal (fluorescence) या Deficient (no fluorescence)। Female carriers: quantitative test चाहिए।

My G6PD test was normal but I had a haemolytic crisis 2 weeks ago. Is the result accurate?

No — the result is almost certainly falsely normal. This is the most important G6PD testing pitfall. During and for 2–4 weeks after a haemolytic crisis, the G6PD-deficient red cells (which carry the least enzyme activity) have been selectively destroyed by haemolysis — the surviving circulating cells are the younger reticulocytes, which have higher G6PD activity even in a deficient person. Testing during this reticulocyte-rich period gives a falsely normal or borderline result that does not reflect the patient's true baseline enzyme activity. Wait 3–4 weeks after full recovery from the haemolytic crisis before testing G6PD — when the blood has returned to steady-state composition. The same principle applies after blood transfusion: wait 3 months (the lifespan of donor red cells). If you had a haemolytic crisis from primaquine or dapsone but the G6PD test was done during or shortly after the crisis — the test should be repeated 4 weeks after recovery.

उत्तर: नहीं — संभवतः falsely normal। Crisis के दौरान G6PD-low cells नष्ट, reticulocytes में activity high। Crisis recovery के 3–4 सप्ताह बाद retest। Blood transfusion के 3 महीने बाद।

My son has G6PD deficiency. Can he take paracetamol for fever?

Yes — paracetamol (acetaminophen) is safe in G6PD deficiency at normal therapeutic doses. It is the recommended fever reducer for G6PD-deficient individuals of all ages. Ibuprofen and aspirin at standard doses are also generally considered safe in G6PD deficiency (though some sources list high-dose aspirin as a caution). The drugs that must be strictly avoided are: primaquine, dapsone, nitrofurantoin, methylene blue, rasburicase, and certain sulphonamides. For his fever: paracetamol (10–15 mg/kg every 6 hours for children). However, fever itself — from infection — is a G6PD haemolysis trigger independently of medication. If he develops dark urine, sudden pallor, or jaundice during a fever illness — this is a haemolytic crisis and requires immediate hospital attention, regardless of whether any triggering drug was given. Treat the underlying infection promptly.

उत्तर: हाँ — Paracetamol G6PD में सुरक्षित है। Ibuprofen (standard dose) भी आमतौर पर सुरक्षित। Avoid: primaquine, dapsone, nitrofurantoin। लेकिन: बुखार स्वयं ट्रिगर है — गहरा मूत्र या पीलापन पर तुरंत अस्पताल।

I am G6PD deficient and need to be treated for P. vivax malaria. Can I take primaquine?

No — primaquine is contraindicated in G6PD deficiency. Primaquine is the only drug that clears P. vivax liver hypnozoites (preventing relapses) — but it causes severe haemolysis in G6PD-deficient individuals. Your options are: (1) Withhold primaquine — treat the acute attack with chloroquine/artemisinin, but accept that P. vivax relapses will likely occur every few months. (2) Weekly low-dose primaquine (0.75 mg/kg once weekly for 8 weeks) — WHO recommends this alternative schedule for mild G6PD deficiency (Class III), under close supervision with weekly haemoglobin and urine checks. This lower-rate schedule gives the body time to replenish G6PD-deficient red cells between doses. (3) Tafenoquine — the newer single-dose anti-relapse drug — is also contraindicated in G6PD deficiency. This decision must be made by a physician or haematologist after reviewing your specific G6PD enzyme activity level, WHO class, and available monitoring capacity.

उत्तर: नहीं — Primaquine G6PD कमी में contraindicated। विकल्प: (1) Primaquine withhold + relapses स्वीकार करें; (2) Weekly low-dose primaquine (Class III में physician supervision); (3) Tafenoquine भी contraindicated। Haematologist से निर्णय लें।

My daughter tested G6PD normal. Does this mean she cannot pass G6PD deficiency to her children?

Not necessarily — the standard qualitative fluorescent spot test can miss heterozygous G6PD carrier females. A female with one normal and one deficient G6PD gene (heterozygous carrier) may have an intermediate enzyme activity that appears "normal" on qualitative testing but is actually a carrier. To reliably determine whether your daughter is a carrier: request a quantitative G6PD enzyme assay (not just qualitative). If quantitative is also borderline, G6PD molecular genotyping (PCR for specific mutations) provides the definitive answer. This is important for family planning: a heterozygous carrier mother has a 50% chance of passing the deficient gene to each child. Sons who inherit the deficient gene will be fully G6PD deficient; daughters who inherit it will be heterozygous carriers.

उत्तर: जरूरी नहीं — qualitative test female carriers miss कर सकता है। Carrier detection: quantitative enzyme assay या molecular genotyping। Carrier माँ: 50% sons में full deficiency, 50% daughters में carrier। Family planning के लिए genetic counselling।

Is fasting required before G6PD test?

No — fasting is not required for the G6PD test. G6PD is an enzyme activity measured in red blood cells — food intake does not affect red cell enzyme levels. You can eat and drink normally before the test. However, the most important preparation requirements are: (1) test in steady state — at least 3–4 weeks after any haemolytic episode; (2) test at least 3 months after any blood transfusion; (3) inform the lab about recent medications (especially primaquine, dapsone) that can deplete G6PD-deficient cells and cause falsely normal results; (4) deliver sample promptly — enzyme activity degrades with time and temperature; (5) use an NABL-accredited lab that handles enzyme assays correctly.

उत्तर: नहीं — उपवास आवश्यक नहीं। सबसे महत्वपूर्ण: steady state में परखें (haemolytic episode के 3–4 सप्ताह बाद, transfusion के 3 महीने बाद)। नमूना promptly deliver करें।

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External References / बाहरी संसाधन

• WHO — G6PD Deficiency: WHO Guidance on G6PD Testing and Primaquine
• NVBDCP India: National Vector Borne Disease Control Programme — Malaria G6PD Guidelines
• MedlinePlus (NIH): G6PD Deficiency — Patient Information

⚠️ Medical Disclaimer / चिकित्सा अस्वीकरण

This article is for educational purposes only. G6PD test results must always be interpreted by a qualified haematologist or physician alongside CBC, clinical history, and medication review. If you or your child develops dark urine, sudden pallor, jaundice, or severe weakness after taking a medication — go directly to the hospital emergency department. Never start primaquine for malaria without G6PD testing. A G6PD-deficient individual should never take a new medication without first verifying it is safe with their doctor.

यह लेख केवल शैक्षिक उद्देश्यों के लिए है। गहरा मूत्र, अचानक पीलापन, पीलिया, या गंभीर कमजोरी पर तुरंत hospital emergency जाएं। G6PD testing के बिना कभी Primaquine न दें। नई दवा लेने से पहले हमेशा doctor से G6PD safety confirm करें।

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