High large platelet ratio may be caused by physiological factors, such as exercise, or pathologic factors, such as thrombocythemia and acute megakaryocytic leukemia. 1. physiological factors: when physiological factors such as exercise, fever, drinking too little water occur, the human body loses a lot of water, and at this time the blood concentration in human blood vessels is relatively high, which leads to a high large platelet ratio. 2. Thrombocytosis: Thrombocytosis can be triggered by bacterial infection, acute blood loss or anemia. Infection by germs can cause the body to secrete more cytokines that can cause thrombocytosis. Acute blood loss leads to higher blood loss and thickening of the blood. Primary thrombocythemia can be caused by abnormal proliferation of megakaryocytes leading to elevated platelets. 3. Acute megakaryocytic leukemia: acute megakaryocytic leukemia is mainly caused by the abnormal proliferation of megakaryocytes, which may manifest as bleeding, fever, hematopoiesis, etc. Large thrombocytosis may occur in some patients at the onset. It is recommended that patients go to the hospital to check the cause of the disease and receive targeted treatment as prescribed by the doctor.