What is iron deficiency anemia?
Iron deficiency anemia is low hemoglobin from depleted iron stores. Ferritin is the most sensitive early marker; hemoglobin falls late. Common in menstruating women and athletes.
Full answer
Iron deficiency anemia is the most common nutritional deficiency worldwide and the leading cause of anemia in menstruating women. The progression: ferritin (iron stores) depletes first, then transferrin saturation falls, then hemoglobin drops. Symptoms — fatigue, exercise intolerance, hair shedding, restless legs, cold extremities — can present at low-normal hemoglobin if ferritin is depleted. oMeds provider review uses ferritin, transferrin saturation, TIBC, hemoglobin, MCV, and RDW together; an 'optimization' ferritin band of 50-150 ng/mL applies regardless of whether anemia is yet present.
Educational. Not a substitute for individualized provider review.
- Ferritin — Primary source · oMeds
- Reviewed by Dr. Laura Purdy, MD, MBA · Clinical Director, oMeds · Last reviewed 2026-05-29