Treatment of Low Ferritin Levels
The treatment for low ferritin levels should include oral iron supplementation with ferrous sulfate 324 mg (65 mg elemental iron) daily or on alternate days as first-line therapy, with intravenous iron reserved for cases with poor absorption, intolerance to oral therapy, or when rapid repletion is needed. 1, 2, 3
Diagnosis and Assessment
Low ferritin is defined as:
Important to note: Patients with inflammatory conditions may have iron deficiency even with ferritin levels up to 100 μg/L 1
Additional testing to consider:
Oral Iron Therapy
Dosing Options:
- Standard dosing: Ferrous sulfate 324 mg (65 mg elemental iron) daily 2
- Alternative dosing: 28-50 mg elemental iron daily or on alternate days to minimize side effects 3
Administration Tips:
- Take on an empty stomach for optimal absorption
- If GI side effects occur, can take with meals (though absorption will be reduced)
- Pair with vitamin C (500 mg) to enhance absorption
- Take with meat protein when possible to improve absorption 1
- Avoid taking with calcium, fiber, tea, coffee, or dairy products 1
Duration:
- Continue for 8-10 weeks minimum
- Recheck ferritin levels after 8-10 weeks of therapy 3
- Target ferritin level: 50-100 μg/L 4
Intravenous Iron Therapy
Indications:
- Poor response to oral therapy
- Intolerance to oral iron (severe GI side effects)
- Conditions with impaired absorption (celiac disease, inflammatory bowel disease)
- Need for rapid iron repletion 1, 5
Administration:
- Total intravenous iron dose should be calculated based on iron deficit formulas
- Doses typically given every 3-7 days until total dose is administered
- Single doses should not exceed maximum recommended dose 1
- Monitor for infusion reactions
Monitoring:
- Serum ferritin levels should be monitored and preferably not exceed 500 μg/L to avoid toxicity 1
- Particularly important in children and adolescents
Special Populations
Athletes:
- Athletes, especially endurance athletes and runners, are at higher risk of iron deficiency
- IV iron supplementation may be more effective for iron-deficient athletes with compromised hemoglobin mass
- Can improve VO₂max and endurance capacity in those with true deficiency 5
Celiac Disease:
- Ensure adherence to gluten-free diet to improve iron absorption
- Consider IV iron if oral therapy fails to improve iron stores 1
Blood Donors:
- Regular blood donors are at increased risk for iron deficiency
- May benefit from iron supplementation between donations 6
Dietary Recommendations
- Increase consumption of iron-rich foods:
- Heme iron sources: Red meat, poultry, fish
- Non-heme iron sources: Legumes, dark green leafy vegetables, fortified cereals
- Avoid iron absorption inhibitors with meals:
- Tea, coffee, calcium supplements, dairy products
- Include iron absorption enhancers with meals:
Follow-up and Monitoring
- Recheck ferritin levels after 8-10 weeks of therapy
- For patients with persistent low ferritin, consider intermittent oral supplementation
- Long-term follow-up with basic blood tests every 6-12 months for those at risk 3
- Avoid overtreatment leading to iron deficiency (ferritin <50 μg/L) or iron overload 4, 3
Common Pitfalls
- Misinterpreting elevated ferritin due to inflammation as adequate iron stores
- Overlooking underlying causes of iron deficiency (blood loss, malabsorption)
- Continuing supplementation despite normal or high ferritin levels
- Inadequate duration of therapy
- Not addressing dietary factors affecting iron absorption 4