Weba cause of thrombocytopenia includes select one: Webwhat are the broad causes for thrombocytopenia? Webwhich diagnostic test can detect destruction of circulating platelets as the cause of thrombocytopenia? 1 hemoglobin 2 bone marrow analysis 3 prothrombin time (pt) 4. Bleeding in the skin may be the first sign of a low platelet count. Many tiny red dots (petechiae) often appear.