Management of Low Iron Stores with Normal Hemoglobin and Iron Saturation
Oral iron supplementation is recommended to replenish depleted iron stores, even in the absence of anemia, using ferrous sulfate 65 mg elemental iron once daily or on alternate days for approximately 3 months. 1
Rationale for Treatment
The primary goal of iron therapy extends beyond correcting anemia to include replenishing body iron stores, improving quality of life, and optimizing physiological function. 1 Low iron stores (ferritin) represent the earliest stage of iron deficiency and warrant treatment to prevent progression to iron-deficiency anemia and associated symptoms such as fatigue, exercise intolerance, and cognitive impairment. 2, 3
Recommended Treatment Approach
First-Line Therapy: Oral Iron
Start with ferrous sulfate 200 mg tablet (65 mg elemental iron) once daily. 1 This represents the most cost-effective and evidence-based initial approach.
Alternative dosing: If gastrointestinal side effects occur, reduce to one tablet every other day, which maintains similar overall iron absorption due to reduced hepcidin stimulation. 1 Alternate-day dosing significantly increases fractional iron absorption compared to daily dosing. 1
Alternative formulations: If ferrous sulfate is not tolerated, consider ferrous fumarate (69-106 mg elemental iron) or ferrous gluconate (37 mg elemental iron). 1
Duration and Monitoring
Continue treatment for approximately 3 months to ensure adequate repletion of iron stores, even though hemoglobin is already normal. 1
Monitor ferritin levels after 8-10 weeks to assess response to therapy. 2
After successful repletion, monitor blood counts every 6 months initially to detect recurrent iron deficiency. 1
When to Consider Intravenous Iron
Parenteral iron should be considered when: 1
- Oral iron is contraindicated, ineffective, or not tolerated after trial of at least two different oral preparations
- Malabsorption conditions exist (celiac disease, inflammatory bowel disease, post-bariatric surgery)
- Chronic inflammatory conditions are present (though your patient has normal iron saturation, suggesting this is less likely)
- Rapid repletion is required
Important Clinical Considerations
Investigation Threshold
There is insufficient evidence to support invasive gastrointestinal investigation in non-anemic iron deficiency unless additional clinical indications exist (such as gastrointestinal symptoms, occult blood loss, or age-related cancer risk factors). 1 This is a critical point—the absence of anemia makes extensive workup less urgent unless other red flags are present.
Ferritin Interpretation
- For healthy adults >15 years, a ferritin cut-off of <30 µg/L indicates iron deficiency requiring treatment. 2
- Ensure C-reactive protein is normal to exclude falsely elevated ferritin from inflammation. 2
Optimization of Oral Iron Absorption
- Take iron on an empty stomach when possible for maximal absorption. 1
- Consider ascorbic acid (250-500 mg) with iron to enhance absorption if response is suboptimal. 1
- Avoid taking iron with calcium, tea, or coffee which inhibit absorption. 2
Common Pitfalls to Avoid
Do not defer treatment awaiting extensive investigations in asymptomatic patients with isolated low ferritin and normal hemoglobin. 1
Avoid excessive dosing: Higher doses (>60-100 mg elemental iron daily) stimulate hepcidin and paradoxically reduce overall iron absorption while increasing side effects. 1
Do not continue long-term daily supplementation once ferritin normalizes, as this provides no benefit and may be harmful. 2
Recognize that modified-release preparations are less suitable for prescribing due to reduced bioavailability. 1
Special Populations
For premenopausal women with menorrhagia, pregnancy, or heavy menstrual bleeding, intermittent oral supplementation may be needed long-term to maintain iron stores, with monitoring every 6-12 months. 2, 3