Elliptocytes/ovalocytes can vary in appearance from slightly oval to thin pencil-shaped forms. Less than 1% of red cells in normal blood are oval. Many examples of elliptocytes can be seen in this smear from a patient with hereditary elliptocytosis(HE). All cases of HE are associated with weakening of membrane skeleton and defective association of proteins that hold the skeleton together. The function of elliptocytes appear to be unaffected in most cases. Notice that the cells vary in shape from slightly oval to cigar-shaped. The largest percentage of elliptocytes is seen on smears from patients with hereditary elliptocytosis. Since many of these patients have no symptoms, the presence of elliptocytes on the smear may be the only diagnostic feature.