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Question 1 of 30

Which test provides a definitive diagnosis of aplastic anemia?

Rationale:
Bone marrow aspiration provides a definitive diagnosis of aplastic anemia. A definitive diagnosis of aplastic anemia requires direct examination of the bone marrow. Bone marrow aspiration and biopsy reveal hypocellularity with a significant reduction or absence of hematopoietic stem cells and their precursors, replaced by fat. This direct assessment of marrow architecture and cellularity is crucial for confirming the profound marrow failure characteristic of aplastic anemia, distinguishing it from other causes of pancytopenia. A: Complete blood count with differential A CBC identifies pancytopenia (low red, white, and platelets), which is suggestive of aplastic anemia but does not reveal the underlying bone marrow failure directly. C: Serum IgG levels Serum IgG levels assess immune function and are not directly indicative of bone marrow cellularity or the presence of aplastic anemia. This test offers no diagnostic value for this specific condition. D: Basic metabolic panel A basic metabolic panel evaluates kidney function, electrolyte balance, and blood glucose, none of which directly diagnose or rule out bone marrow failure like aplastic anemia.