Is an Esophagogastroduodenoscopy (EGD) indicated in patients with low ferritin levels?

Endoscopic Evaluation for Low Ferritin Levels

Bidirectional endoscopy (EGD and colonoscopy) is strongly recommended for asymptomatic postmenopausal women and men with iron deficiency anemia (ferritin <45 ng/mL), and conditionally recommended for asymptomatic premenopausal women. 1, 2

Diagnostic Criteria for Iron Deficiency

• The American Gastroenterological Association (AGA) recommends using a ferritin cutoff of <45 ng/mL to diagnose iron deficiency, rather than the outdated threshold of <15 ng/mL 1, 2
• This threshold provides 85% sensitivity with 92% specificity for iron deficiency 1
• In patients with inflammation or chronic kidney disease, ferritin may be falsely elevated and additional testing may be needed 1, 2

Endoscopic Evaluation Algorithm

1. First, confirm iron deficiency anemia:

   • Hemoglobin <13g/dL in men or <12g/dL in non-pregnant women, AND
   • Ferritin <45ng/mL 1

2. Determine if patient has GI symptoms:

   • If yes: Tailor endoscopic evaluation to symptoms
   • If no: Proceed with evaluation for asymptomatic iron deficiency anemia 1

3. Perform non-invasive testing:

   • Test for H. pylori (non-invasive method)
   • Test for celiac disease with serology 1
   • If either is positive, treat accordingly

4. Proceed with bidirectional endoscopy if non-invasive tests are negative:

   • For men and postmenopausal women: Strong recommendation (moderate quality evidence)
   • For premenopausal women: Conditional recommendation (moderate quality evidence) 1

Evidence Supporting Endoscopic Evaluation

Research demonstrates significant diagnostic yield from endoscopic evaluation in patients with low ferritin:

• In asymptomatic patients with iron deficiency anemia, EGD identified potential sources of blood loss in 28.6% of patients after negative colonoscopy, including erosive/ulcerative lesions and celiac disease 3
• Even in patients with ferritin between 40-100 ng/mL (low-normal range), upper GI findings were identified in 30% of cases, supporting endoscopic evaluation even with borderline ferritin values 4
• The prevalence of bleeding lesions in both upper and lower GI tract is significantly higher in patients with iron deficiency compared to those without iron deficiency 5

Important Considerations and Caveats

• Age and gender impact risk: Elderly patients and men have higher risk of significant pathology, including malignancy 2, 3
• NSAID/ASA use: Patients using NSAIDs or aspirin have higher rates of erosive/ulcerative lesions (36%) 3
• Avoid routine biopsies: The AGA suggests against routine gastric biopsies to diagnose atrophic body gastritis 1
• Small bowel evaluation: For patients with unrevealing bidirectional endoscopy who require antiplatelet/anticoagulant therapy, consider video capsule endoscopy 1
• Common pitfall: Using outdated ferritin cutoffs (<15 ng/mL) may lead to missed diagnoses 2

Special Populations

• Premenopausal women: May reasonably select initial iron supplementation alone if they place higher value on avoiding endoscopy risks and lower value on detecting rare neoplasia 1
• Patients with inflammation: Interpret ferritin in context, as levels up to 100 μg/L may still indicate iron deficiency in inflammatory states 2

In conclusion, EGD is indicated for patients with low ferritin (<45 ng/mL) as part of a comprehensive evaluation for iron deficiency anemia, particularly in men and postmenopausal women, even without gastrointestinal symptoms.