Treatment for Low Ferritin (Iron Deficiency)
Iron deficiency should be treated when it is associated with anemia and/or low ferritin levels, with oral iron supplementation being the first-line therapy for most patients at doses of 100-200 mg/day, while intravenous iron is reserved for specific cases of oral iron failure, malabsorption, or need for rapid repletion. 1
Diagnosis of Iron Deficiency
- Iron deficiency is diagnosed by low serum ferritin (typically <30 μg/L) in individuals without inflammatory conditions or by transferrin saturation less than 20% 2
- For healthy adults aged >15 years, a ferritin cut-off of 30 μg/L is appropriate; for children 6-12 years and adolescents 12-15 years, cut-offs of 15 and 20 μg/L respectively are recommended 3
- Inflammation can falsely elevate ferritin levels, so C-reactive protein should be measured to exclude acute phase reactions when evaluating iron status 3
- Serum ferritin is the most specific indicator of depleted iron stores, especially when used with other tests to assess iron status 1
Oral Iron Therapy
- Typical doses of oral iron supplements are 100-200 mg/day of elemental iron, in divided doses 1
- Common oral iron preparations include:
- Recent data suggest better iron absorption and possibly fewer adverse effects with alternate day dosing 1
- Gastrointestinal side effects are common (constipation, diarrhea, nausea) 1
- Dietary advice is important - integrating heme and free iron regularly into the diet and avoiding inhibitors of iron uptake provides additional benefit 1
- Vitamin C should be co-ingested with non-heme iron sources to enhance absorption, while tea and coffee should be avoided around meal times as they impair iron absorption 1
Intravenous Iron Therapy
- IV iron administration is indicated for patients: 1
- Not reaching target therapeutic goal with oral supplementation
- Requiring fast supplementation (e.g., before elective surgery)
- With repeated failure of oral therapy
- With oral iron intolerance
- With poor absorption (celiac disease, post-bariatric surgery)
- With chronic inflammatory conditions (CKD, heart failure, IBD, cancer)
- With ongoing blood loss
- During second and third trimesters of pregnancy
- When IV iron is required, risk minimization should be addressed as reactions during iron infusions, though very infrequent (<1:250,000 administrations with recent formulations), may be life-threatening 1
- For significant iron deficiency requiring IV treatment, a single IV dose of whole-body iron replacement (1g) should be given over 15 minutes using one of the recent carbohydrate products 1
Monitoring Treatment
- To measure the success of treatment, basic blood tests should be repeated after 8-10 weeks, not earlier after iron infusion as ferritin levels are falsely high 1, 3
- Patients with repeatedly low ferritin will benefit from intermittent oral substitution to preserve iron stores and long-term follow-up, with basic blood tests repeated every 6 or 12 months 3
Special Considerations
- Iron supplementation in the presence of normal or high ferritin values is not recommended and is potentially harmful 1, 3
- For inflammatory bowel disease patients with anemia, intravenous iron should be considered as first-line treatment when disease is clinically active, with previous intolerance to oral iron, or with hemoglobin below 100 g/L 1
- In athletes, particularly female athletes who are at higher risk of iron deficiency, regular monitoring is recommended (once per year in male players and twice per year in female players) 1
Common Pitfalls to Avoid
- Failing to recognize that inflammation can mask iron deficiency by falsely elevating ferritin levels 1
- Administering iron supplements when ferritin is normal or high, which is potentially harmful 1, 3
- Testing too soon after IV iron administration, as ferritin levels will be falsely elevated 1
- Ignoring dietary factors that affect iron absorption (inhibitors like tea/coffee, enhancers like vitamin C) 1
- Not considering alternate day dosing, which may improve absorption and reduce side effects 1