Smear cells are the white blood cells that are damaged during the process of making blood smear, because in the process of making blood smear, it is necessary to rub the slide with pushing slides at a certain angle, and some of the white blood cells are damaged during the rubbing process, which eventually form the smear cells. The smear cells usually have no cytoplasm and are also irregular in shape, and in addition the nucleus is also irregular in shape. Because some leukocytes are damaged during the process of making blood smears, smear cells can be seen in some normal people, but the percentage is usually relatively low, usually no more than 1 in 10,000. However, in certain hematologic disorders, such as chronic lymphocytic leukemia, chronic granulocytic leukemia, and acute myeloid leukemia, smear cells are more likely to be seen in proportions of even more than 1-10%. To confirm the diagnosis of these leukemias, relying on smear cells is never enough; ultimately, a bone marrow aspiration test is required to confirm the diagnosis.