Any platelet disorder affects blood clotting.
Disorders of platelet function can be caused by congenital diseases or acquired conditions. In many cases, the platelet count may be normal or even elevated, but evidence of a bleeding disorder will be present. Myeloproliferative disorders such as primary thrombocytopenia , polycythemia vera, chronic myelogenous leukemia , and myelofibrosis can produce abnormalities in platelet function. Treatment of other disorders may also reduce risk. Some cases are not preventable.