History. A history of easy bleeding or easy bruising should lead to further investigation. Platelet count. Platelet disorders will be discussed later. Using the direct count (reference values 150,000-400,000/mm3; 150-400 x 109/L), a platelet count less than 100,000/mm3 indicates moderate thrombocytopenia, and one less than 50,000/mm3 indicates severe thrombocytopenia. Platelet number can be estimated with […]