What is the appropriate management for a 44‑year‑old patient with iron deficiency anemia characterized by low serum iron, low ferritin, low transferrin saturation, borderline low hemoglobin, normal mean corpuscular volume and low mean corpuscular hemoglobin?

Management of Iron Deficiency Anemia in a 44-Year-Old Patient

This patient requires immediate oral iron supplementation and concurrent investigation for gastrointestinal blood loss, with bidirectional endoscopy reserved for specific high-risk features.

Diagnostic Confirmation

Your patient has absolute iron deficiency anemia confirmed by the following laboratory pattern:

• Ferritin 12 µg/L is definitively diagnostic – values <15 µg/L have 99% specificity for absolute iron deficiency 1, 2
• Transferrin saturation 0.06 (6%) is severely reduced – values <16% confirm impaired iron delivery to bone marrow for red blood cell production 1, 2
• Hemoglobin 110 g/L meets WHO criteria for anemia in women (threshold <115 g/L) 3
• MCH 24 pg (low) and borderline-low MCV 80 fL indicate iron-restricted erythropoiesis, though full microcytosis has not yet developed 1, 3

The elevated transferrin 3.4 g/L (upper limit of normal) represents the body's compensatory attempt to capture more circulating iron when stores are depleted 1.

Immediate Treatment Protocol

Start Oral Iron Without Delay

Begin ferrous sulfate 65 mg elemental iron daily (or 60–65 mg every other day) – do not wait for completion of diagnostic workup 2. Alternate-day dosing improves absorption by 30–50% and reduces gastrointestinal side effects (nausea, constipation, diarrhea) 2.

• Take on an empty stomach for optimal absorption; if gastrointestinal symptoms occur, take with meals 2
• Expected response: hemoglobin should rise ≥10 g/L within 2 weeks 2, 3
• Continue iron for 3 months after hemoglobin normalizes to achieve target ferritin >100 ng/mL and prevent recurrence 2

Mandatory Screening for Underlying Causes

Non-Invasive Testing Required for All Patients

1. Screen for celiac disease with tissue transglutaminase IgA antibodies – celiac disease accounts for 3–5% of iron-deficiency cases and causes treatment failure when missed 1, 2

2. Test for Helicobacter pylori infection using stool antigen or urea-breath test – the organism impairs intestinal iron absorption 1, 2

Indications for Bidirectional Endoscopy (Upper GI + Colonoscopy)

Reserve endoscopy for patients meeting ANY of the following criteria 2:

• Age ≥50 years (higher gastrointestinal malignancy risk)
• Gastrointestinal symptoms: abdominal pain, altered bowel habits, visible blood in stool
• Positive celiac or H. pylori testing requiring confirmation
• Failure to respond to adequate oral iron after 8–10 weeks (absence of ≥10 g/L hemoglobin rise)
• Strong family history of colorectal cancer

For premenopausal women <50 years with heavy menstrual bleeding and no gastrointestinal symptoms, empiric oral iron supplementation without immediate endoscopy is appropriate 2. However, in adult men and postmenopausal women, urgent bidirectional endoscopy is mandatory because iron deficiency may be the sole manifestation of gastrointestinal malignancy 2.

When to Switch to Intravenous Iron

Use intravenous ferric carboxymaltose 15 mg/kg (maximum 1000 mg per dose) when any of the following apply 2, 4:

• Severe oral iron intolerance (marked nausea, constipation, diarrhea)
• Confirmed malabsorption: celiac disease, inflammatory bowel disease, post-bariatric surgery
• Ongoing blood loss exceeding oral replacement capacity
• Lack of hemoglobin response after 8–10 weeks of adequate oral iron
• Chronic inflammatory conditions: chronic kidney disease, heart failure, cancer
• Pregnancy in second/third trimester

Intravenous iron produces reticulocytosis within 3–5 days and yields a mean hemoglobin increase of ≈8 g/L over 8 days, demonstrating superior efficacy in these populations 2.

Follow-Up and Monitoring

• Recheck CBC and ferritin at 8–10 weeks to assess therapeutic response 2, 3
• Target ferritin >100 ng/mL to fully replenish iron stores 2
• For high-risk groups (menstruating females, vegetarians, athletes), schedule ferritin screening every 6–12 months 2

Critical Pitfalls to Avoid

• Do not assume dietary modification alone will correct this degree of deficiency – supplementation is mandatory 1
• Do not discontinue iron once hemoglobin normalizes – an additional 3 months is required for ferritin to reach >100 ng/mL 2
• Do not overlook celiac disease screening – its 3–5% prevalence in iron-deficiency cases leads to treatment failure when missed 1, 2
• Do not delay endoscopic evaluation in high-risk patients (age ≥50, alarm symptoms, treatment failure) – gastrointestinal malignancy can present solely with iron deficiency 2, 5
• Normal MCV does not exclude iron deficiency – this patient's borderline-low MCV 80 fL and low MCH 24 pg confirm iron-restricted erythropoiesis before full microcytosis develops 1, 3