Hello and welcome to HCM, Platelets counts are elevated in various conditions most common being infection and inflammation. Platelet elevation can also occur in neoplastic condition which lead to elevation of platelet number, however, it is important to rule out infection and inflammation before suspecting neoplastic elevation. If the platelet count has been high for long period of time, the cause of elevated platelet count has to be found out. I suggest you to consult a hematologist for clinical assessment, repeat hemogram and bone marrow assessment if necessary. Thanks and take care Dr Shailja P Wahal