From the Guidelines
An endoscopy is typically indicated when ferritin levels fall below 45 ng/mL, as recommended by the AGA with a strong strength of recommendation and high quality of evidence 1. This recommendation is based on the most recent and highest quality study, which suggests that a cutoff of 45 ng/mL is more appropriate than 15 ng/mL for diagnosing iron deficiency in patients with anemia. The investigation should include both upper endoscopy (esophagogastroduodenoscopy) and colonoscopy to evaluate the entire gastrointestinal tract, as iron deficiency often results from chronic, occult blood loss. Key points to consider when evaluating ferritin levels and deciding on an endoscopy include:
- The presence of iron deficiency anemia without an obvious cause
- Additional risk factors for gastrointestinal bleeding or malignancy
- Symptom severity, with urgent evaluation for patients presenting with overt bleeding, significant anemia, or concerning symptoms like unintentional weight loss or persistent abdominal pain
- The AGA's recommendation for bidirectional endoscopy in asymptomatic postmenopausal women and men with iron deficiency anemia, with a strong strength of recommendation and moderate quality of evidence 1
- The importance of considering other potential causes of iron deficiency, such as celiac disease or Helicobacter pylori infection, and testing for these conditions as needed 1.
From the Research
Ferritin Level and Endoscopy Indication
- The ferritin level that indicates an endoscopy is not strictly defined, but several studies provide guidance on when to consider endoscopic evaluation in patients with iron deficiency anemia.
- A study published in 1997 2 included patients with iron deficiency anemia, defined by a serum ferritin level of less than 50 ng/mL, and found that approximately half of these patients had an underlying gastrointestinal lesion.
- Another study from 2001 3 defined iron deficiency anemia as a ferritin level of less than 30 microg/L and found that 85% of patients had a likely cause of iron deficiency anemia detected through endoscopic evaluation.
- A 2007 review 4 recommends an endoscopic evaluation beginning with colonoscopy if the patient is older than 50, but does not specify a particular ferritin level for indicating an endoscopy.
- A 2013 article 5 suggests that a ferritin level of less than 30 μg/L may be a more sensitive cutoff for detecting iron deficiency, but notes that there is no consensus on the diagnostic cutoff.
- A 2008 study 6 found that patients with anaemia without evidence of iron deficiency (ferritin levels above 100 μg/L) had a lower prevalence of bleeding gastrointestinal lesions, but that elderly patients with intermediate ferritin concentrations (30-100 μg/L) may still benefit from gastrointestinal evaluation.
Key Findings
- Ferritin levels can indicate the need for endoscopic evaluation, but the specific cutoff value is not universally agreed upon.
- Patients with iron deficiency anemia, particularly those with ferritin levels below 50 ng/mL or 30 μg/L, may benefit from endoscopic evaluation to detect underlying gastrointestinal lesions.
- Elderly patients with intermediate ferritin concentrations (30-100 μg/L) may also require gastrointestinal evaluation due to a higher yield of bleeding lesions.