Glucose-6-phosphate dehydrogenase (G6PD) screenGlucose-6-phosphate dehydrogenase assay

G6PD deficiency is an X-linked recessive hereditary disease characterised by abnormally low levels of G6PD, a metabolic enzyme involved in the pentose phosphate pathway and especially important in red blood cell metabolism. G6PD deficiency is the most common human enzyme defect. The clinical impact of G6PD deficiency relates to the severity of the deficiency, the age of the patient, and exposure to oxidative agents, eg. exposure to broad beans (favism) and a variety of drugs. G6PD deficiency may result in: • Severe but temporary haemolytic anaemia on exposure to oxidative agents and some physiological stresses • Neonatal jaundice • A chronic haemolytic anaemia

G6PD assay is commonly requested as part of the screening procedure for prolonged neonatal jaundice and for patients likely to be prescribed oxidant drugs, such as primaquine, chloroquine or dapsone.

- Prolonged neonatal jaundice (primarily in male infants)
- Patients who may receive oxidative drugs and who may or may not have a personal history of haemolytic anaemia

Drugs implicated in inducing haemolysis in G6PD deficient individuals include:

- Antimalarials, eg. primaquine, pamaquine and chloroquine
- Sulfonamides, such as sulfanilamide, and mafenide, thiazolesulfone, methylene blue and naphthalene
- Some analgesics, such as aspirin, phenazopyridine and acetanilide
- Some non-sulpha antibiotics (nalidixic acid, nitrofurantoin, isoniazid, dapsone and furazolidone)

6.3-11.2 U/g Hb