What is the treatment for a ferritin level of 5, indicating severe iron deficiency?

Treatment for Severe Iron Deficiency with Ferritin of 5

Oral iron supplementation with ferrous sulfate 324 mg (65 mg elemental iron) taken 2-3 times daily is the first-line treatment for severe iron deficiency with a ferritin level of 5. 1, 2

Diagnosis Confirmation

A ferritin level of 5 μg/L indicates severe iron deficiency, well below the diagnostic thresholds:

• <30 μg/L for adults 1, 3
• <15-20 μg/L for children and adolescents 1
• <45 μg/L as recommended by the American Gastroenterological Association 4

Additional testing to complete the iron profile should include:

• Hemoglobin and hematocrit (to confirm anemia)
• Complete blood count with red cell indices
• Transferrin saturation
• Inflammatory markers (CRP, ESR) to rule out inflammation masking iron deficiency 1

Treatment Approach

Oral Iron Therapy

• First-line treatment: Ferrous sulfate 324 mg (65 mg elemental iron) 2-3 times daily 4, 2
• Take on an empty stomach for optimal absorption
• Consider taking with 500 mg vitamin C to enhance absorption 4
• Alternative formulations if intolerance occurs:
  • Ferrous gluconate (less elemental iron but better tolerated)
  • Ferrous fumarate

Dosing Considerations

• For severe deficiency (ferritin of 5), start with higher frequency (3 times daily)
• If gastrointestinal side effects occur, consider:
  • Reducing to once daily or alternate-day dosing
  • Taking with meals (though this reduces absorption by 40-60%)
  • Switching to a different iron formulation 1, 5

Monitoring Response

• Repeat hemoglobin, ferritin, and transferrin saturation after 8-10 weeks of treatment 1
• A hemoglobin increase <1.0 g/dL at day 14 suggests poor response and may indicate need to switch to IV iron 6
• Target ferritin level: 50-100 μg/L 1
• Continue treatment for 3 months after normalization of hemoglobin to replenish stores 1

When to Consider IV Iron

Intravenous iron should be considered if:

• Intolerance to oral iron despite adjustments
• No improvement in hemoglobin after 14 days of adequate oral therapy 6
• Presence of inflammatory bowel disease with active inflammation 4
• Hemoglobin below 10 g/dL 1
• Malabsorption disorders (celiac disease, post-bariatric surgery) 4, 7

Addressing Underlying Causes

Investigate and treat potential causes of iron deficiency:

• Gastrointestinal blood loss (perform stool occult blood test) 4
• Menstrual blood loss in women
• Malabsorption disorders (consider celiac disease screening)
• Dietary insufficiency
• H. pylori infection 1

Long-term Follow-up

• After normalization, monitor hemoglobin and ferritin every 3-6 months for one year, then annually 1
• Provide maintenance therapy if ferritin drops below 30 μg/L 1, 3
• Avoid long-term daily supplementation once ferritin is normal, as excessive iron can be harmful 3

Common Pitfalls to Avoid

1. Inadequate duration of therapy: Continue treatment for 3 months after hemoglobin normalizes
2. Ignoring poor response: If no improvement after 14 days, consider IV iron 6
3. Missing underlying causes: Always investigate the reason for iron deficiency
4. Overlooking compliance issues: Side effects often lead to poor adherence
5. Using outdated ferritin thresholds: Some labs still use very low cutoffs (<15 μg/L) that miss many cases of iron deficiency 8

By following this approach, most patients with severe iron deficiency will achieve normalization of iron stores and resolution of symptoms within 3-6 months of treatment.