At what serum ferritin level is iron infusion typically recommended for patients with iron deficiency anemia?

Appropriate Iron Levels for Iron Infusion

Intravenous iron therapy is recommended when serum ferritin is <100 ng/mL or when ferritin is between 30-100 ng/mL with transferrin saturation <20%, especially in the presence of inflammation. 1

Diagnostic Criteria for Iron Deficiency

• In patients without inflammation, a serum ferritin <30 ng/mL indicates absolute iron deficiency 1
• In patients with inflammation or cancer, ferritin cutoff should be raised to <100 ng/mL to diagnose iron deficiency 1
• When ferritin is between 30-100 ng/mL with transferrin saturation <20%, a combination of true iron deficiency and anemia of chronic disease is likely 1
• Functional iron deficiency is characterized by low transferrin saturation (<20%) despite normal or elevated ferritin (up to 800 ng/mL) 1

Indications for Intravenous Iron Therapy

First-line IV Iron Therapy Recommended For:

• Patients with clinically active inflammatory bowel disease 1
• Patients with previous intolerance to oral iron 1
• Patients with hemoglobin below 100 g/L 1
• Patients requiring erythropoiesis-stimulating agents 1
• Patients with cancer receiving chemotherapy who have functional iron deficiency 1, 2

Oral Iron Appropriate For:

• Patients with mild anemia whose disease is clinically inactive 1
• Patients without previous intolerance to oral iron 1

Special Considerations for Different Patient Populations

Cancer Patients:

• IV iron is indicated for cancer patients with ferritin <100 ng/mL and transferrin saturation <20% 1
• In functional iron deficiency (ferritin 30-800 ng/mL and TSAT <20%), IV iron can significantly improve hemoglobin levels 2
• For cancer patients with ferritin >800 ng/mL or transferrin saturation ≥20%, IV iron supplementation is not needed 1

Chronic Kidney Disease:

• Iron should be administered to maintain ferritin ≥100 ng/mL and transferrin saturation ≥20% in patients with hemoglobin <110 g/L 1
• In patients requiring high doses of erythropoietic-stimulating agents, IV iron may be considered even with ferritin >800 ng/mL if transferrin saturation is <25% 1

Inflammatory Bowel Disease:

• After successful treatment with IV iron, re-treatment should be initiated when ferritin drops below 100 mg/L 1

Monitoring and Safety

• Monitor for hypersensitivity reactions during and after IV iron administration for at least 30 minutes 3
• Check serum phosphate levels in patients requiring repeat courses of treatment, as hypophosphatemia can occur 3, 2
• For patients with elevated ferritin levels, carefully assess the balance between benefits and risks of ongoing iron administration 1

Clinical Pitfalls to Avoid

• Don't rely solely on ferritin without considering inflammation status - ferritin is an acute phase reactant that increases during inflammation 1, 4
• Don't overlook functional iron deficiency in patients with chronic inflammatory conditions, even when ferritin appears normal 1, 4
• Don't wait for severe anemia to develop before considering IV iron therapy in high-risk patients 1
• Don't assume oral iron will be effective in patients with inflammatory conditions, as hepcidin activation can inhibit iron absorption 1, 2