Diagnostic strategy for geriatric patients with thrombocytopenia. Initial evaluation requires laboratory studies, including review of peripheral blood smear to exclude platelet clumping. After true thrombocytopenia is established, further assess for concurrent hemolytic anemia and white blood cell disorders to narrow differential diagnosis and alert clinicians to diagnoses that may warrant urgent action, such as TMA or suspicion for infection. When diagnosis is suspicious for hematologic malignancy or aplastic anemia, bone marrow aspiration and biopsy should be considered to establish diagnosis. BM, bone marrow; DIC, disseminated intravascular coagulation; LFT, liver function tests; HTN, hypertension; HUS, hemolytic uremic syndrome; TTP, thrombotic thrombocytopenic purpura.