High total platelet count may be caused by primary thrombocythemia, chronic granulocytic leukemia, true erythrocytosis and other conditions. 1. Primary thrombocythemia: the direct cause of this disease is not clear, it may be related to gene mutation, cytokines, bone marrow hematopoietic stem cell clonal proliferation and other factors. The onset of primary thrombocythemia is more insidious, some patients are asymptomatic at the onset of the disease, and the total platelet count is high only in the examination, while some patients may also have bleeding, thrombus, splenomegaly and so on. 2. Chronic granulocytic leukemia: the cause of the disease is more complicated, and it is mostly considered to be related to the exposure to hair dyes, ionizing radiation and other factors. The onset of the disease is slow, and patients often have symptoms such as low fever, excessive sweating, emaciation, fatigue, splenomegaly, etc. Some patients may have no obvious symptoms, and only abnormal increase in peripheral blood is found in the examination, which may also be manifested as high total platelet count. 3. True erythrocytosis: the cause of this disease is still unclear, and it is considered to be related to factors such as increased sensitivity of stem cells to erythropoietin and uncontrolled tumorigenic proliferation of stem cells. In the early stage of the disease, it can only be found during physical examination, and most of the patients will have high total platelet count, and with the development of the disease, patients can also have itchy skin, liver and spleen, headache, tinnitus, dizziness and thrombosis. High total platelet count is also seen in infection, bleeding, hemolysis, increased reactivity, it is recommended that patients with high total platelet count should identify the cause of the disease in time and take targeted treatment.