Large platelets are platelets with a platelet volume greater than or equal to 12 fl. The large platelet ratio refers to the low percentage of large platelets in the total number of all platelets. The common causes of low large platelet ratio are thrombocytosis and large platelet reduction. A, thrombocytosis 1, myeloproliferative diseases: thrombocytosis myeloproliferative diseases including chronic granulocytic leukemia, primary thrombocytosis, true erythrocytosis, myelofibrosis, etc.; 2, reactive thrombocytosis: mainly acute and chronic inflammation, iron deficiency anemia, acute hemorrhage, malignancy, fracture, hypoxia and cancer, etc. Second, large thrombocytopenia 1, reduced platelet production: reduced platelet production is seen in acute leukemia, acute radiation disease, aplastic anemia, etc.; 2, excessive platelet destruction: excessive platelet destruction is commonly seen in hypersplenism, immune thrombocytopenic purpura; 3, increased platelet consumption: increased platelet consumption can be seen in familial thrombocytopenia, giant platelet syndrome, diffuse intravascular coagulation, etc. When there is a low platelet ratio, you need to go to the hospital as soon as possible to clarify the cause, because a low platelet ratio is not a disease in itself, it can occur normally, or the organism may appear in the presence of the above-mentioned diseases.