The mean platelet volume, also called MPV, represents the average volume of individual platelets in peripheral blood, which is the average of the volumes of all platelets in the blood. If the mean platelet volume is small, it means that the average volume of platelets in the blood is small, with a normal reference value of 9-13. The size of MPV is often a direct reflection of the maturation of peripheral platelets and an indirect reflection of the hematopoietic activity of the bone marrow, and is often analyzed in conjunction with changes in platelet count. Because changes in these two indicators often occur simultaneously, they can be used to identify the etiology of thrombocytopenia. In general, a decrease in platelet count and an increase in mean platelet volume is due to increased platelet destruction. A decrease in platelet count and a decrease in mean platelet volume is due to a bone marrow lesion.