What should you know about a G6PD blood test?

G6PD helps red blood cells handle oxidative stress. If activity is low, cells can break down more easily after particular medicines, infections, or foods. The test uses a blood sample and is interpreted with your symptoms, family background, medicines, and other blood results. A result can be harder to interpret during or soon after a haemolytic episode, when many older red cells have been lost. Your clinician may repeat testing if the result does not fit the clinical picture.

Usually, you can eat and drink normally unless the laboratory gives different instructions. Tell the clinician about recent illness, jaundice, dark urine, transfusion, and all medicines or supplements. Do not stop prescribed treatment on your own. A low activity result may lead to advice about avoiding specific triggers and checking medicines before taking them; it does not by itself explain every cause of tiredness or anaemia.

Seek urgent care for yellowing of the skin or eyes, dark urine, severe weakness, breathlessness, chest discomfort, fainting, or rapidly worsening symptoms after a new medicine or infection. Arrange medical review for persistent fatigue, repeated episodes of anaemia, or a family history of G6PD deficiency.

Ask why testing is recommended, whether recent illness or transfusion could affect interpretation, when results will be available, and which medicines or foods need checking. Ask whether relatives or a baby in the family should be assessed and what symptoms would indicate red-cell breakdown.