Iron Deficiency Anemia: Treatment Approach
Based on your laboratory values showing iron deficiency (ferritin 10.9 µg/L, transferrin saturation 24%, elevated TIBC 507), you should initiate oral iron supplementation as first-line therapy, with consideration for investigation of underlying causes given the severity of iron depletion. 1
Laboratory Interpretation
Your results confirm absolute iron deficiency anemia:
- Ferritin 10.9 µg/L is highly specific for depleted iron stores (diagnostic threshold <15 µg/L has 99% specificity) 1
- Transferrin saturation 24% is borderline low (iron deficiency typically <20%) 1
- TIBC 507 is elevated, consistent with iron deficiency 1
- Hemoglobin 13.5 g/dL is at the lower limit of normal for males or within normal range for females 1
- MCV 85.8 fL shows normocytic pattern (not yet microcytic), indicating relatively early iron deficiency 1
Treatment Algorithm
First-Line: Oral Iron Supplementation
Start with oral ferrous sulfate 325 mg daily (containing 65 mg elemental iron) or on alternate days 1, 2, 3:
- Dosing strategy: 100-200 mg elemental iron daily in divided doses is standard, though alternate-day dosing may improve absorption and reduce side effects 1
- Timing: Take on empty stomach for optimal absorption; if not tolerated, take with meals (preferably with meat protein and 500 mg vitamin C) 1
- Duration: Continue for 8-10 weeks minimum, then recheck hemoglobin, ferritin, and iron studies 1, 4
- Goal: Correct anemia AND replete iron stores (ferritin >30 µg/L) 4, 5
Common Pitfalls with Oral Iron
- Gastrointestinal side effects (constipation, nausea, abdominal pain) occur frequently and reduce compliance 1, 4
- Avoid excessive doses: Preparations with 28-50 mg elemental iron may be better tolerated than higher doses 4
- Do not recheck labs too early: Ferritin levels are falsely elevated immediately after iron supplementation 1
When to Consider Intravenous Iron
- Oral iron intolerance or failure after 8-10 weeks
- Malabsorption conditions (celiac disease, post-bariatric surgery, inflammatory bowel disease)
- Ongoing blood loss exceeding oral replacement capacity
- Chronic inflammatory conditions (though your normal MCHC 32.5 suggests no inflammation) 1
- Need for rapid iron repletion before surgery 1
IV iron dosing: Calculate total iron deficit based on hemoglobin deficit and need to rebuild stores; ferric carboxymaltose allows single large doses (up to 1000 mg) over 15 minutes 1
Safety consideration: Keep ferritin <500 µg/L during IV therapy to avoid iron overload toxicity, especially important for long-term management 1
Investigation of Underlying Cause
You require evaluation for the source of iron loss 1:
- Gastrointestinal investigation should be considered at any level of anemia with iron deficiency, particularly with ferritin <30 µg/L 1
- Stool guaiac testing for occult GI bleeding is recommended 1
- In premenopausal women: Heavy menstrual bleeding is the most common cause; GI investigation may not be warranted without other symptoms 1
- In men or postmenopausal women: GI evaluation (bidirectional endoscopy) is strongly indicated as colorectal cancer risk is significant 1
Additional Diagnostic Considerations
Rule out other causes of microcytosis if iron studies were normal 1:
- Hemoglobin electrophoresis for thalassemia (particularly with appropriate ethnic background)
- However, your low ferritin confirms iron deficiency as the primary cause
Monitoring Strategy
Reassess after 8-10 weeks of oral iron therapy 1, 4:
- Repeat complete blood count, ferritin, iron, TIBC, and transferrin saturation
- Expected response: Hemoglobin should increase by 1-2 g/dL; ferritin should rise toward >30 µg/L
- If inadequate response: Consider IV iron or investigate for ongoing blood loss, malabsorption, or non-compliance 4, 5
Long-term management for recurrent deficiency 4: