Schistocytes are fragments of red blood cells. They come in various shapes (such as crescents or triangles) rather than in the pale-centered biconcave disks that are characteristic of normal, intact red blood cells.
A check for abnormal red blood cells is performed systematically when irregularities are found in an automated complete blood count or when a blood smear (examination of the blood under the microscope) is specifically prescribed by the doctor. While all possible varieties of abnormal red blood cells are checked for (unless a specific request is made), the test results report mentions only the abnormal varieties found in the specimen.
Schistocytes indicate an abnormality in the blood vessel walls that causes the membrane of several red blood cells to rupture (in conditions such as disseminated intravascular coagulation, hemolytic uremic syndrome and other hemolytic syndromes).