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Difficulty: MediumInterpreting Laboratory Results

Match each patient's laboratory profile with the most likely diagnosis.

  • Hb 8.2 g/dL, MCV 72 fL, Ferritin 8 ng/mL, TIBC 480 µg/dL, Serum Iron 25 µg/dLIron deficiency anemia
  • Hb 9.5 g/dL, MCV 84 fL, Ferritin 520 ng/mL, TIBC 210 µg/dL, Serum Iron 35 µg/dLAnemia of chronic inflammation
  • Hb 10.8 g/dL, MCV 62 fL, Ferritin 180 ng/mL, TIBC 310 µg/dL, Serum Iron 95 µg/dL, HbA2 5.5%Beta-thalassemia trait
  • Hb 7.9 g/dL, MCV 115 fL, Reticulocyte count 0.4%, elevated methylmalonic acid, elevated homocysteineVitamin B12 deficiency

Answer

Profile 1 matches Iron deficiency anemia; Profile 2 matches Anemia of chronic inflammation; Profile 3 matches Beta-thalassemia trait; Profile 4 matches Vitamin B12 deficiency.
Each laboratory profile uniquely identifies a specific mechanism of anemia. Absolute iron deficiency causes depleted stores (low ferritin, high TIBC). Chronic inflammation causes hepcidin-mediated iron sequestration (high ferritin, low TIBC). Beta-thalassemia trait causes a globin synthesis defect (marked microcytosis, normal iron, high HbA2). Vitamin B12 deficiency impairs DNA synthesis (macrocytosis, high MMA, high homocysteine).

Step-by-Step Solution

1
Analyze the first laboratory profile.
Identified low MCV, markedly decreased ferritin, elevated TIBC, and low serum iron.
These findings reflect depleted total body iron stores characteristic of absolute iron deficiency anemia.
2
Analyze the second laboratory profile.
Identified normal or borderline low MCV, elevated ferritin, decreased TIBC, and low serum iron.
This pattern shows adequate or high iron stores that are sequestered in macrophages due to hepcidin effects, characteristic of anemia of chronic inflammation.
3
Analyze the third laboratory profile.
Identified very low MCV out of proportion to the degree of anemia, normal iron stores, and elevated HbA2.
Elevated HbA2 (>3.5%) with microcytosis and normal iron studies confirms a diagnosis of beta-thalassemia trait.
4
Analyze the fourth laboratory profile.
Identified macrocytosis, low reticulocyte count, and elevated levels of both methylmalonic acid (MMA) and homocysteine.
While both folate and vitamin B12 deficiency cause macrocytic anemia with elevated homocysteine, only vitamin B12 deficiency also causes elevated methylmalonic acid.

Key Concept

Differentiation of anemia etiologies based on comprehensive hematologic and biochemical laboratory parameters.
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Interpreting Laboratory Results

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