G6PD and G6PD deficiency: To reduce the risk of drug-induced hemolysis, patients should be tested for G6PD deficiency before prescribing an 8-aminoquinoline drug.14 This can be achieved with either qualitative or quantitative tests.12 Qualitative G6PD diagnostics categorize individuals as normal or deficient; however, these tests are only reliable at a threshold of about 30% enzyme activity and thus label heterozygous females with > 30% G6PD activity as normal.