What is the cause of high platelet count?

Normal platelet count is (100-300) ×10^9/L, if there is increased phenomenon, it is generally divided into two cases: primary increase and reactive increase. Primary increase is more common in polycythemia vera, primary thrombocythemia, chronic myelocytic leukemia, etc. Reactive increase is generally seen in various acute infections, such as acute gastroenteritis, acute appendicitis, acute pneumonia, acute cholecystitis, etc.