Iron Deficiency Anemia Treatment
Start oral iron supplementation immediately with ferrous sulfate 200 mg three times daily (or alternate-day dosing) to restore hemoglobin and replenish iron stores, with your lab values (ferritin 39 ng/mL, iron saturation 19%) confirming absolute iron deficiency requiring treatment. 1
Diagnostic Confirmation
Your laboratory values definitively indicate iron deficiency:
- Ferritin 39 ng/mL is below the 45 ng/mL threshold recommended by the American Gastroenterological Association for diagnosing iron deficiency 1
- Iron saturation 19% is below 20%, further confirming absolute iron deficiency 2
- These values indicate depleted iron stores requiring repletion 1
First-Line Treatment: Oral Iron
Initiate oral iron therapy as follows:
- Ferrous sulfate 200 mg three times daily is the most cost-effective first-line option 1
- Alternative formulations include ferrous gluconate or ferrous fumarate if ferrous sulfate is not tolerated 1
- Alternate-day dosing (rather than daily) may improve absorption and reduce side effects by avoiding hepcidin upregulation 1
- Take on an empty stomach when possible for optimal absorption, though taking with food is acceptable if it improves tolerance 1
- Add 500 mg vitamin C to enhance iron absorption, especially if response is poor 1
Monitoring Response
Reassess hemoglobin at 2-4 weeks:
- Expect a 2 g/dL increase in hemoglobin after 3-4 weeks of oral iron 1
- A hemoglobin increase <1.0 g/dL at day 14 identifies patients who should transition to intravenous iron (sensitivity 90.1%, specificity 79.3%) 3
- Continue oral iron for 3 months after anemia correction to fully replenish iron stores 1
When to Switch to Intravenous Iron
Consider IV iron if:
- No response (<1 g/dL hemoglobin increase) after 4 weeks of oral iron despite adequate compliance 1, 3
- Intolerance to oral iron (gastrointestinal side effects like nausea, constipation, abdominal pain) 1
- Ongoing blood loss exceeding intestinal absorption capacity 4
- Concomitant inflammatory conditions (though not indicated by your labs) 1
Common pitfall: Only 21% of early non-responders to oral iron will respond to continued oral therapy, while 65% respond to IV iron 1. Don't persist with oral iron beyond 4-6 weeks without documented response.
Identify and Address Underlying Cause
Mandatory evaluation includes:
- Dietary assessment for inadequate iron intake 1
- Menstrual history if premenopausal woman (menorrhagia is a leading cause) 1, 5
- Gastrointestinal evaluation in men and postmenopausal women to exclude GI blood loss or malabsorption 1, 5
- Screen for celiac disease, H. pylori infection, and NSAID use 1
Long-Term Management
After correction:
- Monitor hemoglobin and ferritin every 3 months for one year, then annually 1
- Resume oral iron if ferritin drops below 30 ng/mL or hemoglobin decreases 1
- Further investigation is only needed if iron stores cannot be maintained with supplementation 1
Critical caveat: Failure to respond to oral iron is usually due to poor compliance, continued blood loss, malabsorption, or misdiagnosis—not inadequate dosing 1. Address these factors before escalating therapy.