Management of Low Ferritin with Normal Hemoglobin in a 51-Year-Old Female
Continue oral iron supplementation (ferrous sulfate 324 mg daily, equivalent to 65 mg elemental iron) for at least 3 months after ferritin normalization to fully replenish iron stores, with a target ferritin of at least 50 ng/mL. 1, 2
Current Clinical Status
Your patient has shown improvement from ferritin 14 to 24 ng/mL while maintaining normal hemoglobin, indicating she is responding to treatment but remains iron deficient. A ferritin of 24 ng/mL still represents depleted iron stores that require continued supplementation. 1
Treatment Approach
Continue Iron Supplementation
- Ferrous sulfate 200-324 mg (65 mg elemental iron) three times daily remains the most effective and cost-efficient option 1, 2
- Treatment must continue for 3 months after hemoglobin and ferritin normalize to adequately replenish body iron stores 1
- The target ferritin should be at least 50 ng/mL before considering stopping therapy 1
Monitoring Strategy
- Recheck ferritin and hemoglobin in 3 months to assess response 1
- Once ferritin normalizes (>50 ng/mL), continue iron for an additional 3 months, then monitor at 3-month intervals for the first year, then annually 1
- If ferritin or hemoglobin falls below normal during follow-up, resume oral iron supplementation 1
Important Clinical Context for Premenopausal Women
At age 51, this patient is likely perimenopausal, making menstrual blood loss the most probable etiology 1. However, the British Society of Gastroenterology guidelines emphasize that:
- All patients with confirmed iron deficiency should receive iron supplementation regardless of the underlying cause 1
- Menstruating women commonly develop iron deficiency (5-10% prevalence) due to menstrual loss, pregnancy, and breastfeeding 1
- While menstrual loss is the likely cause, if dietary deficiency is excluded and iron supplementation fails to maintain normal levels, gastrointestinal evaluation should be considered 1
Symptomatic Considerations
Even with normal hemoglobin, ferritin levels below 50 ng/mL can cause symptoms including fatigue 3, 4. Research demonstrates that:
- Iron supplementation significantly reduces fatigue in nonanemic women with ferritin <50 μg/L (47.7% improvement vs 28.8% with placebo) 4
- Symptoms can occur at ferritin levels <100 ng/mL in some patients 3
- Treatment should address quality of life, not just laboratory values 3, 4
Common Pitfalls to Avoid
- Do not stop iron therapy prematurely when hemoglobin normalizes—ferritin must also normalize and stores must be replenished 1
- Do not assume normal hemoglobin excludes clinically significant iron deficiency—tissue iron depletion occurs before anemia develops 3, 5
- Avoid iron-fortified foods and supplemental vitamin C during the initial treatment phase if hemochromatosis is a consideration, though this is unlikely given the low ferritin 1
- Do not use ferritin alone to guide therapy—consider it alongside hemoglobin levels and clinical symptoms 1
When to Consider Alternative Approaches
If oral iron is not tolerated or ferritin fails to rise appropriately after 3 months of adequate oral supplementation, consider intravenous iron 1. However, given the current positive response (ferritin rising from 14 to 24), continuing oral therapy is appropriate 1.
If iron deficiency recurs after adequate repletion and cessation of therapy, further investigation for occult blood loss is warranted 1, though in a perimenopausal woman, ongoing menstrual losses remain the most likely explanation 1.