hematology and oncology
Glucose 6 Phosphate Dehydrogenase (G6PD) Deficiency
Diagnosis of G6PD Deficiency
Peripheral smear G6PD assay The diagnosis is considered in patients with evidence of acute hemolysis, particularly males with a direct antiglobulin–negative hemolytic anemia (see Diagnosis ). Anemia, jaundice, and reticulocytosis develop during hemolysis. The peripheral smear may reveal RBCs that appear to have a blister (blister cells) or have one or more "bites" (1-micron wide) taken from the cell periphery (bite cells) and RBCs with inclusions termed Heinz bodies, which are particles of denatured hemoglobin, which can be recognized only by special stains. These cells may be visible early during the hemolytic episode but do not persist in patients with an intact spleen, which removes them. Testing for G6PD activity is available. However, during and immediately after a hemolytic episode, tests may yield false-negative results because of destruction of the older, more deficient RBCs and the production of reticulocytes, which are rich in G6PD. Thus, testing may need to be repeated several weeks after the acute event. Several screening tests are available, including point-of-care tests; positive results should be confirmed with a quantitative test. 