Ovalocytes are red blood cells that have an oval shape rather than the usual round doughnut shape. Ovalocytes are more fragile than normal red blood cells. About 1% of ovalocytes are found in a normal complete blood count. This percentage increases in all types of anemia and can be as high as 10% of the total RBCs: infectious anemias, cancer and leukaemia, thalassemias, etc.). Hereditary ovalocytosis is a genetic disease that affects the red blood cell wall and causes the formation of many ovalocytes. This condition also results in mild anemia due to the exaggerated destruction of these ovalocytes.
Elliptocytes are highly flattened ovalocytes that resemble sticks. Elliptocytes (elliptocytosis) are most often found in highly noticeable genetic ovalocytoses with more than 50% of red cells present in the form of ovalocytes or elliptocytes.