Haematological Investigation Blood Film Marrow Coagulation Tests

The answer first

The haematological investigation panel in physician practice comprises the full blood count (FBC) and peripheral blood film (PBF), the bone marrow aspirate and trephine biopsy, and the coagulation screen (PT/INR, APTT, fibrinogen, D-dimer, mixing studies, specific factor assays). The FRACP candidate must defend three high-yield skills: (1) the morphological pattern recognition on the blood film (macrocytosis, microcytosis, leucoerythroblastic picture, blast forms, schistocytes); (2) the indications for bone marrow biopsy (cytopenias of unclear cause, suspected leukaemia, lymphoma, myeloma, myeloproliferative neoplasm, staging of disseminated disease); and (3) the interpretation of an isolated prolonged APTT (heparin contamination, factor deficiency, lupus anticoagulant, or a specific inhibitor) — discriminated by the mixing study. [1] [6]

The answer-first synthesis is: take a structured history, examine for organomegaly, lymphadenopathy, and bleeding; perform FBC and PBF as the first step; supplement with biochemistry, iron studies, B12 and folate, reticulocyte count, LDH, and haemolysis screen; reserve bone marrow biopsy for cytopenias or malignant patterns; and interpret coagulation tests with the mixing study before requesting a panel of factor assays. [2] [7]

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