Platelet specific volume, refers to the volume of platelets in peripheral blood as a percentage of the total blood volume. There are two types of high platelet ratio: i. Increase in the number of platelets in the blood: caused by a relative increase in the number of platelets. The common causes of increased platelet count are primary thrombocytosis, true erythrocytosis, chronic granulocytic leukemia, and early stages of myelofibrosis, as well as certain acute infectious diseases, such as acute pneumonia, acute gastritis, acute appendicitis, etc., which can also cause an increase in platelet count. Sometimes certain malignant tumors and hemolytic diseases can also cause an increase in the number of platelets. Second, plasma volume reduction: the most common is a variety of dehydration, such as severe vomiting, diarrhea, a lot of sweating, etc., due to the concentration of plasma volume caused by high platelet ratio. After rehydration, the high platelet ratio will gradually return to normal.