G6PD catalyzes the initial step in the hexose monophosphate shunt and is critical in protecting RBCs from oxidant injury. Deficiency of G6PD results in rigidity and lysis of RBCs, preferentially affecting older cells. G6PD deficiency is a hereditary (sex linked) abnormality.
Screening assay: reported as normal or deficient.
Normal range (quantitative assay): 7.0 " “20.5 U/g Hb.
Use
The G6PD assay is used when G6PD deficiency is suspected (abnormal red cell break down).
Interpretation
Decreased In
Hemolytic anemia
All persons with favism (but not all persons with decreased G6PD have favism)
Limitation
This assay should not be used following a hemolytic crisis in African Americans who carry the A ¢ ˆ ’ variant, because reticulocytes (elevated after acute hemolysis) may have sufficient enzyme to give erroneous normal results. Most individuals with G6PD deficiency as appropriate.