What is the appropriate management for a patient with iron deficiency anemia, as indicated by hypoferritinemia, elevated TIBC, and low iron saturation, with normal albumin levels?

Management of Iron Deficiency Anemia

This patient has absolute iron deficiency anemia requiring iron replacement therapy and investigation to identify the underlying cause, with bidirectional endoscopy (gastroscopy and colonoscopy) as the first-line diagnostic approach. 1

Interpretation of Laboratory Values

Your iron studies confirm absolute iron deficiency:

• Ferritin 104.2 ng/mL with transferrin saturation 14% indicates true iron deficiency despite the ferritin being above traditional cut-offs 1
• The British Society of Gastroenterology guidelines specify that ferritin <45 μg/L with transferrin saturation <16% defines iron deficiency in the absence of inflammation 1
• Your transferrin saturation of 14% is clearly below the 16-20% threshold, confirming inadequate iron availability for erythropoiesis 1
• The elevated TIBC of 515 (raised total iron-binding capacity) further supports iron deficiency 1
• Normal albumin 5.2 suggests adequate nutritional status and makes pure malnutrition less likely 1

Immediate Management: Iron Replacement Therapy

First-Line: Oral Iron

Start oral ferrous sulfate 325 mg daily or on alternate days as first-line therapy 2:

• Dosing of 28-50 mg elemental iron minimizes gastrointestinal side effects while maintaining efficacy 3
• Alternate-day dosing may improve absorption by avoiding hepcidin upregulation that occurs with daily dosing 1
• Take with vitamin C to enhance absorption; avoid tea, coffee, and calcium supplements around dosing times 1
• Avoid taking within 2 hours of tetracycline antibiotics due to drug interactions 4
• Common side effects include black stools, constipation, nausea, and diarrhea 4

Response Assessment

Recheck hemoglobin after 2 weeks - a rise of ≥10 g/L (≥1 g/dL) confirms iron deficiency even if initial studies were equivocal 1:

• Continue oral iron for 8-10 weeks, then repeat complete iron studies 3
• If no response after 4 weeks of oral iron, consider intravenous iron 1

When to Use Intravenous Iron

Switch to IV iron if 1, 2:

• Intolerance to oral iron (gastrointestinal side effects)
• Malabsorption (celiac disease, inflammatory bowel disease, post-bariatric surgery)
• Ongoing blood loss
• Chronic inflammatory conditions (though your normal albumin makes this less likely)
• Need for rapid correction

Mandatory Investigation for Underlying Cause

Who Needs Investigation?

All men and postmenopausal women with new iron deficiency anemia require gastrointestinal investigation regardless of hemoglobin level, as this may represent occult malignancy 1:

• Investigation should be considered at any level of anemia in the presence of iron deficiency 1
• More urgent investigation is warranted if hemoglobin <120 g/L in men or <100 g/L in postmenopausal women 1

Initial Diagnostic Workup

Before endoscopy, obtain 1:

1. Urinalysis or urine microscopy - to exclude urinary blood loss 1
2. Celiac disease serology (tissue transglutaminase antibody) - found in 3-5% of iron deficiency anemia cases 1
3. Detailed history focusing on:
   • Gastrointestinal symptoms (change in bowel habits, blood in stool, dyspepsia)
   • NSAID or aspirin use (stop if possible) 1
   • Dietary history (vegetarian/vegan diet, inadequate intake) 3, 2
   • Menstrual history in premenopausal women 2
   • Family history of gastrointestinal malignancy or hereditary conditions 1

Endoscopic Investigation

Bidirectional endoscopy (gastroscopy AND colonoscopy) is the standard first-line investigation 1:

• Both upper and lower GI endoscopy should be performed because dual pathology occurs in 1-10% of cases, especially in older patients 1
• At gastroscopy, obtain duodenal biopsies even if celiac serology is negative if there are suggestive features (diarrhea, weight loss) 1
• If colonoscopy is not feasible, CT colonography is a reasonable alternative 1

If Initial Endoscopy is Normal

Consider small bowel investigation if 1:

• Inadequate response to iron replacement therapy
• Recurrent iron deficiency anemia after initial correction
• Severe anemia persists
• Clinical suspicion of small bowel pathology remains high

Capsule endoscopy is the primary small bowel investigation, followed by enteroscopy if lesions are identified 5

Common Pitfalls to Avoid

• Do not dismiss ferritin >100 ng/mL as excluding iron deficiency - transferrin saturation <16% is diagnostic regardless of ferritin level in the absence of inflammation 1
• Do not skip investigation in favor of empiric iron therapy alone - underlying malignancy must be excluded 1, 6
• Do not perform only upper OR lower endoscopy - both are required due to risk of dual pathology 1
• Do not continue daily oral iron indefinitely without monitoring - recheck iron studies at 8-10 weeks 3
• Do not give intravenous iron if ferritin is already >150 ng/mL unless there is clear functional iron deficiency with ongoing erythropoietin therapy 1

Special Considerations

If you are a premenopausal woman with heavy menstrual bleeding and no gastrointestinal symptoms, investigation may be deferred initially with close monitoring 1. However, the threshold for investigation should be low if symptoms develop or iron deficiency recurs 1.

If celiac serology is positive, confirm with small bowel biopsy and treat accordingly, as this may be the sole cause of iron deficiency 1.