Is intravenous (IV) iron indicated for a patient with a ferritin level of 83 ng/mL and iron saturation of 17%?

IV Iron for Ferritin 83 ng/mL and Iron Saturation 17%

Yes, IV iron is indicated for this patient, as these values meet criteria for functional iron deficiency (ferritin <100 ng/mL and transferrin saturation <20%), particularly if the patient has anemia or specific comorbidities such as chronic kidney disease, heart failure, inflammatory bowel disease, or cancer. 1

Clinical Context Determines Treatment Approach

The decision to use IV iron depends critically on the underlying clinical scenario:

If Patient Has Cancer with Chemotherapy-Induced Anemia:

• IV iron combined with an erythropoiesis-stimulating agent (ESA) is recommended for functional iron deficiency defined as ferritin <800 ng/mL and transferrin saturation <20%. 1
• IV iron has superior efficacy compared to oral iron and should be considered for supplementation in this population. 1
• IV iron monotherapy (without ESA) has insufficient evidence and is not routinely recommended for functional iron deficiency in cancer patients. 1
• Data are insufficient to consider IV iron as monotherapy for treatment of functional iron-deficiency anemia in the cancer setting. 1

If Patient Has Chronic Kidney Disease (Not on Dialysis):

• IV iron is indicated when ferritin ≤100 ng/mL OR transferrin saturation ≤20%, which this patient meets on both criteria. 1
• Multiple KDIGO trials used iron-starting criteria of ferritin ≤100 ng/mL or TSAT ≤20%, with iron-stopping criteria of ferritin ≥800 ng/mL and TSAT ≥20% or TSAT ≥40%. 1
• The OLYMPUS trial recommended IV iron if patients were intolerant or unresponsive to oral iron with Hb <8.5 g/dL and ferritin <100 ng/mL or TSAT <20%. 1

If Patient Has Chronic Heart Failure:

• IV iron is indicated for iron deficiency defined as ferritin <100 ng/mL OR ferritin 100-300 ng/mL with TSAT <20%. 1, 2
• The CONFIRM-HF trial demonstrated that IV ferric carboxymaltose improved 6-minute walk distance by 25 meters compared to placebo (p=0.007) in heart failure patients with iron deficiency. 2
• Treatment improved exercise capacity even in patients without anemia (Hb ≥15 g/dL were excluded, but many had Hb >12 g/dL). 2

If Patient Has Absolute Iron Deficiency (No Inflammatory Condition):

• With ferritin 83 ng/mL and TSAT 17%, this represents absolute iron deficiency requiring treatment. 3, 4
• Oral iron (ferrous sulfate 325 mg daily or on alternate days) is typically first-line therapy for uncomplicated absolute iron deficiency. 3
• IV iron is indicated if: oral iron is not tolerated, there is impaired absorption (celiac disease, post-bariatric surgery, atrophic gastritis), ongoing blood loss, or during second/third trimester pregnancy. 3, 4

Diagnostic Thresholds Across Conditions

The definition of iron deficiency requiring treatment varies by clinical context:

• General population/absolute iron deficiency: Ferritin <30 ng/mL and TSAT <15% 1, 3
• Functional iron deficiency (cancer, CKD): Ferritin <100 ng/mL OR TSAT <20% 1
• Heart failure: Ferritin <100 ng/mL OR (ferritin 100-300 ng/mL with TSAT <20%) 1, 2
• Upper treatment threshold: Generally ferritin <800 ng/mL 1

Route of Administration

IV iron has superior efficacy to oral iron in patients with:

• Chronic inflammatory conditions (cancer, CKD, heart failure, IBD) where hepcidin upregulation impairs oral iron absorption 1, 3
• Functional iron deficiency requiring ESA therapy 1
• Ongoing blood loss 3
• Oral iron intolerance or malabsorption 3, 4

Oral iron is appropriate for uncomplicated absolute iron deficiency without inflammatory conditions, malabsorption, or ongoing losses. 3, 5

Common Pitfalls

• Do not withhold IV iron based solely on ferritin >30 ng/mL in patients with chronic inflammatory conditions, as ferritin is an acute-phase reactant and may be falsely elevated. 1
• Transferrin saturation <20% is the key diagnostic criterion for functional iron deficiency, even when ferritin appears adequate. 1
• Avoid iron supplementation in patients with active infection due to concerns about promoting bacterial growth. 1
• Test doses are required for iron dextran and strongly recommended for patients with drug allergies receiving ferric gluconate or iron sucrose. 1