G6PD deficiency

An enzyme deficiency that makes RBCs more susceptible to oxidative damage. This oxidative damage is in the hemoglobin molecules which precipitates out as Heinz bodies which are then deposited on RBC membrane and can be phagocytized by splenic macrophages leading to bite cells (RBCs that look like someone has taken a bite out of them). Conditions that may increase the chance of oxidative damage in these patients include infections, certain Sulfa drugs, or fava beans.