Large platelets are those with an average platelet volume over 11 fL. The proportion of large platelets in the peripheral blood of a normal person is 8%-16%, and more than 16% is a high ratio of large-vessel platelets. High large platelet ratio is commonly seen in the following conditions: First, it refers to excessive destruction of platelets in the peripheral blood, but the bone marrow has a good compensatory function, and in order to compensate for the number of platelets in the peripheral blood, the immature and bulky large platelets are released early. One of the most common clinical disorders is immune thrombocytopenic purpura, in which peripheral platelets are destroyed due to the autoantibodies produced and immature large platelets in the bone marrow are released early to compensate for the reduced platelet count. The second, in some patients with acute granulocytic leukemia, also presents with a high percentage of large platelets.