There are many variants of G6PD deficiency. The Mediterranean variant is common in Sothern Europe, Northern Africa, and the Middle East and is characterized by very low levels of the enzyme and severe reactions to drugs. While other forms such as the A- variant found in southern Africa and South America can have higher enzyme levels, patients treated with Primaquine can still have severe reactions requiring hospitalization and blood transfusions.

Some doctors have found that giving Primaquine only once per week and significantly extending the treatment duration can be acceptable, but this isn’t always possible and creates compliance risks. Testing for the enzyme condition is not always available and the tests become less sensitive once a patient has malaria. In Brazil doctors have made the case that consistently testing for the deficiency would be more cost effective than treating those with severe reactions. Successful patient screening still doesn’t deal with the fundamental issue of how to treat those patients with malaria and G6PD without hospital admission.