Routine blood test is a laboratory examination of the quantity and quality of red blood cells and white blood cells in the blood, which mainly includes four parts: red blood cell count, hemoglobin measurement, white blood cell count, and white blood cell classification. It is generally not possible to rule out leukemia by a single blood test, and there are many different types of leukemia, with different types causing different changes in blood cells. Most people with leukemia have an abnormally high white blood cell count, but there may be normal or decreased counts, and there may be some variation in blood composition, hemoglobin reduction, platelet changes, etc. Therefore, if leukemia is suspected, other tests for leukemia can be further improved when there are abnormal blood count indicators. It is recommended that after routine blood tests for suspected leukemia, if there are abnormalities, peripheral blood smears, bone marrow smear staining microscopy, cytochemistry, blood biochemistry, immunological tests, chromosomal and molecular biology tests can be further improved and compared with the clinical symptoms of leukemia in combination with the specific symptoms of the test subjects to provide a more accurate basis for the exclusion or confirmation of leukemia. Leukemia, also known as blood cancer, is a disease of the blood system, mainly divided into acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia. The clinical symptoms are more complicated, mainly including fever, weakness, bleeding and anemia. Since there are differences in the type and degree of disease in different patients, it may be possible to miss or misdiagnose leukemia if only routine blood test results are used to determine whether a patient has leukemia. For those who have been diagnosed with leukemia, they should actively cooperate with the doctor for treatment. Early diagnosis and early treatment will help improve the quality of survival of leukemia patients.