What is the next step in managing iron deficiency anemia with a ferritin level of 30, transferrin saturation (TSAT) of 22, and erythropoietin (EPO) level of 3, while currently taking 100mg oral iron daily?

Management of Iron Deficiency with Current Laboratory Values

You should increase your oral iron dose to at least 200 mg of elemental iron daily (which you are currently not meeting with 100mg) and consider switching to intravenous iron therapy if you have any gastrointestinal symptoms, poor compliance, or if your hemoglobin is below 10 g/dL. 1

Understanding Your Iron Status

Your laboratory values indicate functional iron deficiency:

• Ferritin 30 ng/mL is below the target of ≥100 ng/mL 1
• TSAT 22% is marginally above the minimum threshold of 20%, but still suboptimal 1
• EPO level of 3 is inappropriately low for your degree of iron deficiency, suggesting you may benefit from erythropoietin therapy if anemia is present 1

The combination of low ferritin and borderline TSAT indicates insufficient iron stores to support optimal erythropoiesis. 1

Immediate Action: Optimize Oral Iron Dosing

Your current 100mg daily dose is inadequate. Guidelines specify that oral iron should be administered at a minimum daily dose of 200 mg of elemental iron for adults, typically divided into 2-3 doses. 1

Specific oral iron recommendations:

• Ferrous sulfate 325mg tablets contain 65mg elemental iron - take 3-4 tablets daily 1
• Ferrous fumarate 325mg tablets contain 108mg elemental iron - take 2 tablets daily 1, 2
• Take iron without food or other medications for optimal absorption, though taking with meals can minimize gastrointestinal discomfort 1, 3
• Add at least 100mg ascorbic acid (vitamin C) daily to enhance absorption 2

When to Switch to Intravenous Iron

Consider IV iron as first-line therapy if any of the following apply:

• Hemoglobin below 100 g/L (10 g/dL) 1
• Gastrointestinal side effects from oral iron (nausea, constipation, diarrhea) 3, 4
• Poor compliance with oral regimen 4
• Chronic kidney disease requiring hemodialysis 1
• Active inflammatory bowel disease 1
• Need for erythropoietin therapy 1

IV iron dosing protocols:

• Initial loading: 100-125 mg IV weekly for 8-10 weeks (total 800-1,250 mg) 1
• Alternative: 500-1,000 mg iron dextran as single infusion after 25mg test dose 1
• Maintenance: 25-125 mg IV weekly once targets achieved 1

Monitoring Strategy

Check TSAT and ferritin monthly until you achieve target levels, then every 3 months thereafter. 1

Target iron parameters:

• Ferritin ≥100 ng/mL 1
• TSAT ≥20% (ideally 30-50%) 1, 5
• Ferritin should not exceed 800 ng/mL to avoid iron overload 1
• TSAT should not exceed 50% to prevent toxicity 1

Critical Pitfalls to Avoid

Do not continue inadequate oral iron dosing. Most patients receiving 100mg daily will fail to maintain adequate iron stores, particularly if they have ongoing blood loss or increased erythropoietic demand. 1

Do not assume oral iron is working without monitoring. Even with 200mg daily dosing, oral iron frequently fails to maintain adequate iron status in patients with high iron demands, with absorption limited when ferritin exceeds 200 ng/mL. 1, 4

Do not delay IV iron if oral therapy fails. Studies consistently show IV iron is superior to oral iron in achieving hemoglobin targets and maintaining iron stores, with faster response times and better tolerability. 1, 4

Avoid iron overload. Withhold iron supplementation if TSAT exceeds 50% or ferritin exceeds 800 ng/mL, and recheck levels in 2-3 months. 1