Interpreting Labs for Iron Deficiency Anemia

Diagnostic Approach

The American Gastroenterological Association recommends that serum ferritin is the most powerful test for diagnosing iron deficiency anemia, with additional tests like transferrin saturation, hemoglobin, and red cell indices providing a complete diagnostic picture 1
The Centers for Disease Control and Prevention suggests that complete blood count (CBC) with red cell indices is the first step in evaluating for iron deficiency anemia 2
Hemoglobin and hematocrit are commonly used screening tests due to low cost and ease of performance, but they are late indicators of iron deficiency, according to the Centers for Disease Control and Prevention 2, 3
Red cell indices (MCV, MCH, MCHC) provide sensitive indication of iron deficiency in the absence of chronic disease or hemoglobinopathy, as stated by the European Society for Medical Oncology 1, 4
Elevated red cell distribution width (RDW >14.0%) with microcytosis strongly suggests iron deficiency anemia, according to the American Society of Hematology 4

The European Society of Gastrointestinal Endoscopy recommends that iron supplementation is recommended for all patients with iron deficiency anemia 6, 1
The goal is to normalize both hemoglobin levels and iron stores, as stated by the American College of Gastroenterology 6
An increase in hemoglobin of at least 2g/dL within 4 weeks of treatment indicates adequate response, according to the European Crohn’s and Colitis Organisation 6
Oral iron should be the initial treatment for most patients, as recommended by the National Institute for Health and Care Excellence 1, 5

In inflammatory states, ferritin may be falsely elevated as an acute phase reactant, according to the European League Against Rheumatism 6, 4
Use higher ferritin threshold (<100 μg/L) to diagnose iron deficiency when inflammation is present, as stated by the American College of Rheumatology 6
All premenopausal women with iron deficiency anemia should be screened for celiac disease, according to the American Gastroenterological Association 1, 5
Pregnant women may require higher doses of iron supplementation due to increased demands, as recommended by the World Health Organization 3, 7