Which laboratory value is commonly used to screen for iron deficiency anemia?

• A. Serum ferritin level
• B. Hemoglobin level
• C. Mean corpuscular volume
• D. Serum transferrin

Answer: (A)

Screening for iron deficiency anemia hinges on assessing iron stores. Serum ferritin reflects stored iron in the body, so its level mirrors total iron stores. In iron deficiency, ferritin drops earliest, making it the most sensitive indicator for detecting deficiency before anemia develops. Hemoglobin shows whether anemia is present but doesn’t tell you about iron stores, and mean corpuscular volume changes later and isn’t specific to iron deficiency. Serum transferrin tends to rise as stores deplete, but ferritin directly measures stores, making it the best initial screen. Keep in mind ferritin can rise with inflammation, which can mask iron deficiency, so clinical context matters.