Gastrointestinal Evaluation of Iron Deficiency Anemia

Publication Date: August 15, 2020
Last Updated: July 6, 2022

Key Points

Key Points

  • Anemia is a common diagnosis in both men and women, and iron deficiency is the most common cause of anemia worldwide.
  • The aim of this guideline is to outline an evidence-based approach to the initial diagnosis and evaluation of this commonly encountered clinical condition.
Group Prevalence in the US
Iron Deficient
Men aged 16–69 years 2%
Women aged 12–49 years 12%
Women aged 50–69 years 9%
Iron Deficiency Anemia
Women aged 20-49 years 4%
Women aged 50-69 years 3%
Overall 2.9%



GI Evaluation of Iron Deficiency Anemia Clinical Decision Support Tool

GI Evaluation of Iron Deficiency Anemia Clinical Decision Support Tool (cont’d)


In patients with anemia, the AGA recommends using a cutoff of 45 ng/mL over 15 ng/mL when using ferritin to diagnose iron deficiency. (High, Strong)
Comment: In patients with inflammatory conditions or chronic kidney disease, other laboratory tests such as C-reactive protein, transferrin saturation, or soluble transferrin saturation, may be needed in conjunction with ferritin to diagnose iron deficiency anemia.
In asymptomatic postmenopausal women and men with iron deficiency anemia, the AGA recommends bidirectional endoscopy over no endoscopy. (Moderate, Strong)
In asymptomatic premenopausal women with iron deficiency anemia, the AGA suggests bidirectional endoscopy over iron replacement therapy only. ( Moderate , Conditional (weak) )
Comment: Patients who place a high value on avoiding the small risk of endoscopy, particularly those who are young and might have other plausible reasons for IDA, and a low value on the very small risk of missing a gastrointestinal malignancy would reasonably select an initial course of iron replacement therapy and no initial bidirectional endoscopy.
In patients with iron deficiency anemia without other identifiable etiology after bidirectional endoscopy, the AGA suggests noninvasive testing for Helicobacter pylori, followed by treatment if positive, over no testing. ( Low , Conditional (weak) )
In patients with iron-deficiency anemia, the AGA suggests against the use of routine gastric biopsies to diagnose atrophic gastritis. ( Very Low , Conditional (weak) )
In asymptomatic adult patients with iron deficiency anemia and plausible celiac disease, the AGA suggests initial serologic testing, followed by small bowel biopsy only if positive, over routine small bowel biopsies. ( Very Low , Conditional (weak) )
Comment: Celiac disease is a well-recognized cause of iron deficiency anemia, even in asymptomatic patients, and therefore must be considered in the differential diagnosis of iron deficiency anemia.
In uncomplicated asymptomatic patients with iron deficiency anemia and negative bidirectional endoscopy, the AGA suggests a trial of initial iron supplementation over the routine use of video capsule endoscopy. ( Very Low , Conditional (weak) )
Comment: Caution needs to be applied in patients with comorbid conditions where the identification of small bowel pathology will change medical management, such as the use of anticoagulation and/or antiplatelet therapy.

Recommendation Grading


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