What is the appropriate referral process for a male patient diagnosed with iron deficiency anemia?

Referral Process for Male with Iron Deficiency Anemia

All men with confirmed iron deficiency anemia require urgent gastrointestinal evaluation with bidirectional endoscopy (both upper endoscopy and colonoscopy) to exclude gastrointestinal malignancy, as approximately one-third will have underlying pathological abnormalities, most commonly in the GI tract. 1

Confirm the Diagnosis Before Referral

• Verify anemia: Hemoglobin <13 g/dL in men 1
• Confirm iron deficiency: Serum ferritin <45 ng/mL is the single most useful marker, though ferritin can be falsely elevated in inflammatory conditions 1
• Alternative confirmation: If iron studies are equivocal, a hemoglobin rise ≥10 g/L within 2 weeks of iron therapy strongly suggests absolute iron deficiency 1

Pre-Referral Testing to Expedite Workup

Before making the gastroenterology referral, complete non-invasive testing to guide the endoscopic evaluation:

• Celiac disease screening: Tissue transglutaminase antibody (IgA type) with total IgA level, as celiac disease is found in 3-5% of all iron deficiency anemia cases 2, 3
• H. pylori testing: Non-invasive testing (stool antigen or urea breath test) 1
• Urinalysis: To exclude urinary tract bleeding as an alternative source 2
• Comprehensive medication history: Explicitly document all NSAID use (including over-the-counter ibuprofen, naproxen, aspirin), anticoagulants, and antiplatelet agents, as NSAIDs are common and frequently unreported causes of occult gastrointestinal blood loss 2

Urgency of Referral

The British Society of Gastroenterology guidelines emphasize that investigation should be considered at any level of anemia in the presence of iron deficiency, though the case is stronger with more severe degrees of anemia. 1

• Fast-track referral (within 2 weeks): Hemoglobin <11 g/dL warrants urgent evaluation per NICE guidelines, though this threshold will miss some colorectal cancers in men 1
• Standard urgent referral: Any confirmed iron deficiency anemia in men without obvious explanation should be referred urgently because gastrointestinal malignancies can present this way, often without specific symptoms 1

What to Include in the Referral

Provide the gastroenterologist with:

• Complete blood count with indices (hemoglobin, MCV, MCH) 1
• Iron studies (ferritin, transferrin saturation, TIBC) 1
• Results of celiac serology and H. pylori testing 1
• Detailed medication list emphasizing NSAIDs and anticoagulants 2
• Presence or absence of gastrointestinal symptoms (abdominal pain, weight loss, change in bowel habits, dyspepsia) 1
• Urinalysis results 2

Expected Gastroenterology Evaluation

The gastroenterologist will perform bidirectional endoscopy as the standard diagnostic approach:

• Upper endoscopy (esophagogastroduodenoscopy): With duodenal biopsies if celiac serology is positive or clinical suspicion remains high, to evaluate for gastric cancer, peptic ulcer disease, angiodysplasia, and celiac disease 1, 2, 3
• Colonoscopy: To exclude colorectal cancer and polyps, which are the most common causes of occult gastrointestinal blood loss in men 1, 3
• Avoid routine biopsies: Reserve duodenal biopsies for positive celiac serologies or endoscopic abnormalities; reserve gastric biopsies for H. pylori only with endoscopic abnormality if non-invasive testing was negative 1

If Initial Endoscopy is Negative

For patients with unrevealing bidirectional endoscopy who have recurrent or refractory iron deficiency anemia:

• Video capsule endoscopy: To evaluate the small bowel, particularly if the patient requires antiplatelet or anticoagulant therapy 1, 3
• Consider small bowel imaging: CT or MRI enterography if red flags suggest inflammatory or malignant small bowel disease (involuntary weight loss, abdominal pain, elevated CRP) 4

Common Pitfalls to Avoid

• Don't assume all anemia in men is from gastrointestinal bleeding: This misses treatable malabsorption (celiac disease) and medication-induced causes (NSAIDs) 2
• Don't accept "normal" ferritin at face value: In the context of chronic inflammation or kidney disease, ferritin levels up to 100 ng/mL may still represent iron deficiency 1
• Don't delay referral for a trial of iron therapy: While iron supplementation should be started, investigation must proceed concurrently to exclude malignancy 1
• Don't stop at finding one cause: Multiple causes may coexist in the same patient (e.g., celiac disease plus NSAID use) 3