A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 63-year-old man with a history of diabetes mellitus presents with complaints of fatigue. He lives alone and has not seen a doctor in 10 years. He does not exercise, eats a poor diet, and drinks 1-2 beers per day. He does not smoke. He has never had a colonoscopy. Labs show a hemoglobin of 8.9 g/dL (normal 13.5 - 17.5), mean corpuscular volume of 70 fL (normal 80-100), serum ferritin of 400 ng/mL (normal 15-200), TIBC 200 micrograms/dL (normal 250-420), and serum iron 50 micrograms/dL (normal 65-150). Which of the following is the cause of his abnormal lab values?
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A
Vitamin deficiencyIncorrect. B12/folate deficiency causes macrocytic anemia (high MCV) — opposite of this patient's microcytic picture.
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B
Mineral deficiencyIncorrect. Iron deficiency would show LOW ferritin and HIGH TIBC; this patient has high ferritin and low TIBC, ruling out simple iron deficiency.
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C
Mineral excessIncorrect. Iron overload (hemochromatosis) causes elevated iron and transferrin saturation with normal or high MCV — not microcytosis with low serum iron.
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D
Chronic inflammationCorrect. anemia of chronic disease shows microcytic anemia with HIGH ferritin (inflammation-driven storage trapping), LOW TIBC, and LOW serum iron from hepcidin-mediated iron sequestration.
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E
Bone marrow infiltrationIncorrect. Bone marrow infiltration (myelophthisic anemia) typically causes a leukoerythroblastic peripheral smear with teardrop cells and pancytopenia, not the isolated microcytic anemia with elevated ferritin pattern seen here.
↑ Tap an answer to reveal the reasoning
Answer: D. Microcytic anemia (low Hgb, low MCV) with HIGH ferritin, LOW TIBC, and LOW serum iron is the classic pattern of anemia of chronic disease (anemia of inflammation), not iron deficiency. Iron deficiency would show LOW ferritin and HIGH TIBC (the body upregulates transferrin to grab any available iron). In anemia of chronic disease, inflammation drives hepcidin release from the liver — hepcidin inhibits ferroportin on enterocytes and macrophages, trapping iron in storage (high ferritin) and preventing its delivery to erythroid precursors (low serum iron). Inflammation also suppresses erythropoietin and shortens RBC survival.
Causes of chronic inflammation underlying this picture include chronic infections, autoimmune disease, and malignancy. In a 63-year-old man who has never had a colonoscopy and presents with microcytic anemia, the workup must include colonoscopy to rule out colon cancer — which can drive both chronic inflammation and occult blood loss. The current iron studies pattern is ACD, but malignancy is a likely underlying driver.
Distractors: vitamin deficiency (B12, folate) causes macrocytic anemia, not microcytic. Mineral (iron) deficiency would give low ferritin/high TIBC. Mineral excess (hemochromatosis) gives elevated iron AND elevated transferrin saturation with normocytic indices.
**Why each option:**
**A.** B12/folate deficiency causes macrocytic anemia (high MCV) — opposite of this patient's microcytic picture.
**B.** Iron deficiency would show LOW ferritin and HIGH TIBC; this patient has high ferritin and low TIBC, ruling out simple iron deficiency.
**C.** Iron overload (hemochromatosis) causes elevated iron and transferrin saturation with normal or high MCV — not microcytosis with low serum iron.
**D.** Correct — anemia of chronic disease shows microcytic anemia with HIGH ferritin (inflammation-driven storage trapping), LOW TIBC, and LOW serum iron from hepcidin-mediated iron sequestration.