Practice Guidelines

Iron Deficiency Anemia: Guidelines from the American Gastroenterological Association


Am Fam Physician. 2021 Aug ;104(2):211-212.

Author disclosure: No relevant financial affiliations.

Key Points for Practice

• In anemia, iron deficiency is best diagnosed using a ferritin threshold of less than 45 ng per mL.

• Patients with IDA should receive noninvasive testing for H. pylori and celiac disease.

• Bidirectional endoscopy is recommended in all adults with IDA.

• Video capsule endoscopy is not recommended in asymptomatic adults with IDA.

From the AFP Editors

Iron deficiency anemia (IDA) is the most common cause of anemia worldwide. It affects 3% of adults and is slightly more common in women younger than 50 years. The American Gastroenterological Association (AGA) developed guidelines for the evaluation of IDA in adults.

Diagnosing Iron Deficiency

The AGA defines anemia as a hemoglobin level of less than 13 g per dL (130 g per L) in men and less than 12 g per dL (120 g per L) in patients who are not pregnant. Serum ferritin testing is commonly used to diagnose iron deficiency in patients with anemia. Based on a systematic review, the AGA recommends using a ferritin threshold value of less than 45 ng per mL (45 mcg per L) for diagnosing iron deficiency in patients with anemia. This threshold has 85% sensitivity and 92% specificity for iron deficiency. Without anemia, the ferritin threshold for iron deficiency is uncertain. Ferritin testing is less accurate in patients with chronic inflammatory conditions or chronic kidney disease, and additional tests including serum iron, transferrin saturation, soluble transferrin receptor, and C-reactive protein can help diagnose iron deficiency.

Noninvasive Testing

Several common conditions associated with IDA can be diagnosed noninvasively, before or after endoscopy. Frequent blood donation, nutritional deficiencies, or malabsorption syndromes may be suggested by initial evaluation.

Helicobacter pylori infection is associated with iron deficiency caused by atrophic gastritis and hypochlorhydria, which reduce iron absorption. Treating H. pylori infection improves the benefit of iron supplementation in anemia. After

Author disclosure: No relevant financial affiliations.

Coverage of guidelines from other organizations does not imply endorsement by AFP or the AAFP.

This series is coordinated by Michael J. Arnold, MD, contributing editor.

A collection of Practice Guidelines published in AFP is available at



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