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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Glucose-6-phosphate dehydrogenase deficiency

Haematology and transfusion · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

Acute haemolysis with shock, chest pain, syncope, severe breathlessness, haemoglobinuria, oliguria, hyperkalaemia or rapidly falling haemoglobin requires immediate ABCDE assessment, cessation of the trigger, renal and haematology support and clinically indicated transfusion. A jaundiced newborn at risk of G6PD deficiency requires urgent bilirubin measurement and treatment through the NICE neonatal-jaundice pathway.

Synopsis

Recognise inherited vulnerability to oxidative haemolysis, remove precipitating infections, foods and medicines, interpret enzyme testing at the correct time and prevent recurrent and neonatal harm.

  • G6PD deficiency is an X-linked red-cell enzyme disorder that impairs NADPH and reduced-glutathione defence; heterozygous females can be clinically affected because X-chromosome inactivation is variable.
  • Many people are asymptomatic between episodes. Infection, fava beans and specific oxidant medicines cause abrupt jaundice, dark urine, pallor, fatigue, abdominal or back pain and falling haemoglobin.
  • The film may show bite cells and blister cells after splenic removal of Heinz-body-containing membrane; supravital staining detects Heinz bodies but is timing dependent and specialist led.
  • Confirm haemolysis with reticulocytes, bilirubin, LDH, haptoglobin, renal function, urinalysis and film. DAT is usually negative and helps identify an immune alternative.
  • A normal enzyme activity result during acute haemolysis or soon after transfusion can be falsely reassuring because deficient older cells have disappeared and reticulocytes or donor cells predominate.
  • Stop the precipitating medicine or food, treat infection and support hydration, renal function and oxygen delivery. There is no routine drug that reverses an acute enzyme defect.
  • Rasburicase is contraindicated in G6PD deficiency because hydrogen peroxide generation can provoke severe haemolysis and methaemoglobinaemia; assess at-risk ancestry before treatment when time permits.
  • Give the patient and primary-care record a diagnosis-specific medicine warning, explain that risk depends on the exact drug and context, and check current BNF and product information rather than relying on memory.

    • Key red flags

    Acute oxidant episode

    Jaundice, pallor, dark urine, fatigue and back or abdominal pain beginning after infection, fava beans or a recognised medicine suggests triggered haemolysis.

    Intravascular severity

    Haemoglobinuria, rapid haemoglobin fall, rising creatinine, oliguria, hyperkalaemia, chest pain or syncope indicates organ-threatening haemolysis and urgent support.

    Neonatal presentation

    Early or rapidly rising jaundice in a baby with relevant ancestry or family history raises G6PD-related hyperbilirubinaemia and requires urgent bilirubin management.

    Investigation priorities

    01
    FBC, serial haemoglobin and absolute reticulocytesFirst step

    Quantify severity, trajectory and marrow compensation.

    Management branches

    Acute haemolysisRemove the oxidant and protect organs

    Dark urine, jaundice and falling haemoglobin occur during infection or after a plausible food, medicine or chemical exposure.

    1. Stop the suspected trigger, treat infection promptly, use ABCDE and obtain FBC, reticulocytes, film, bilirubin, LDH, haptoglobin, DAT, renal profile, potassium, urinalysis and group and screen.
    2. First-line care is supportive hydration and renal, urine-output and oxygen-delivery monitoring; red-cell transfusion is the preferred escalation for clinically important symptomatic anaemia rather than a fixed universal number.
    3. Escalate shock, chest pain, syncope, oliguria, hyperkalaemia, rapidly falling haemoglobin or diagnostic uncertainty to senior haematology, renal, transfusion and critical-care support.

    Key medicines

    RasburicaseDo not administer to a patient with confirmed G6PD deficiency; use the tumour-lysis protocol's supported alternative and specialist metabolic monitoring instead.The SmPC contraindicates use in G6PD deficiency because severe haemolysis and methaemoglobinaemia can occur. Assess higher-risk ancestry before treatment when feasible, stop immediately if either reaction develops and seek urgent specialist care rather than reflexively using methylene blue, which may worsen haemolysis in G6PD deficiency.
    Folic acid for chronic haemolysisA specialist may prescribe 5 mg by mouth once daily when a chronic haemolytic variant creates sustained increased folate requirement; review duration regularly.Check vitamin B12 status before prolonged use and avoid routine indefinite prescribing after a single brief episode. Continued haemolysis needs specialist diagnosis, gallstone and transfusion review.
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    Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
    Sources

    Sources and review status

    National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

    • BNF G6PD deficiency guidanceUK medicine-risk principles and prescribing cautions for oxidant haemolysis.
    • NHS Genomics Education G6PD deficiencyInheritance, variable expression in females, triggers, diagnosis and genomic context.
    • Fasturtec product informationRasburicase contraindication, haemolysis and methaemoglobinaemia risk in G6PD deficiency.
    • NICE CG98 neonatal jaundice recommendationsAge- and gestation-specific bilirubin measurement, treatment and urgent neonatal management.

    Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

    Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom