Macrocytic normochromic anemia— which test will confirm the type of anemia?

Macrocytic normochromic anemia— which test will confirm the type of anemia?

• A. Coombs Test
• B. Schilling Test
• C. Oral Iron Absorption Test
• D. Bone marrow biopsy

Answer: (B)

Macrocytic normochromic anemia often arises from a deficiency of vitamin B12 or folate, because these vitamins are essential for DNA synthesis in developing red cells. To identify the specific cause, you need to assess B12 absorption and the role of intrinsic factor. The Schilling test does that by giving a small oral dose of radiolabeled B12 and measuring how much is excreted in the urine. If absorption is poor, you suspect B12 deficiency. The test is then repeated with intrinsic factor added; if absorption improves, it points to pernicious anemia due to intrinsic factor deficiency. The other tests don’t directly pinpoint this B12-related issue: the Coombs test screens for autoimmune hemolysis, not macrocytosis; an oral iron absorption test assesses iron uptake (relevant to iron deficiency, which is usually microcytic); and a bone marrow biopsy can show megaloblastic changes but doesn’t identify the specific cause.

Macrocytic normochromic anemia often arises from a deficiency of vitamin B12 or folate, because these vitamins are essential for DNA synthesis in developing red cells. To identify the specific cause, you need to assess B12 absorption and the role of intrinsic factor. The Schilling test does that by giving a small oral dose of radiolabeled B12 and measuring how much is excreted in the urine. If absorption is poor, you suspect B12 deficiency. The test is then repeated with intrinsic factor added; if absorption improves, it points to pernicious anemia due to intrinsic factor deficiency. The other tests don’t directly pinpoint this B12-related issue: the Coombs test screens for autoimmune hemolysis, not macrocytosis; an oral iron absorption test assesses iron uptake (relevant to iron deficiency, which is usually microcytic); and a bone marrow biopsy can show megaloblastic changes but doesn’t identify the specific cause.