A person with hemolytic anemia breaks down red blood cells before the red blood cells are completely mature. This results in a lower number of red blood cells in the bloodstream, called anemia.

Normally, the produces red blood cells in the bone marrow, the blood cells mature, and then they are removed from the blood stream when they die. If red blood cells are removed too quickly, the bone marrow is unable to produce enough red blood cells to keep up with the loss.