Does a patient with iron deficiency anemia, normal Hemoglobin (Hb) level, and low Ferritin level require intravenous (IV) iron therapy?

Management of Iron Deficiency with Normal Hemoglobin

Oral iron supplementation is recommended for this patient with iron deficiency (ferritin 29 ng/mL) despite normal hemoglobin (14.5 g/dL), as intravenous iron is not indicated at this time.

Diagnostic Assessment

The patient presents with:

• Normal hemoglobin (14.5 g/dL)
• Low ferritin (29 ng/mL)

This represents non-anemic iron deficiency, as:

• Ferritin <30 ng/mL is diagnostic of iron deficiency even without inflammation 1
• Normal hemoglobin levels do not exclude iron deficiency, as ferritin depletion precedes anemia development

Treatment Algorithm

Step 1: Confirm Iron Deficiency

• Ferritin <30 ng/mL confirms absolute iron deficiency even with normal hemoglobin 2, 1
• Consider checking transferrin saturation (TSAT) to further assess iron status
  • TSAT <20% would further support iron deficiency diagnosis

Step 2: Select Appropriate Treatment

1. For patients with normal hemoglobin and ferritin <30 ng/mL:

   • Oral iron is first-line therapy 1
   • Recommended: Ferrous sulfate 325 mg daily or on alternate days

2. IV iron is NOT indicated when:

   • Hemoglobin is normal (14.5 g/dL)
   • No evidence of malabsorption, intolerance to oral iron, or chronic inflammatory condition
   • No ongoing blood loss requiring rapid iron repletion

Step 3: Monitoring Response

• Repeat ferritin and hemoglobin in 8-10 weeks after initiating oral iron 3
• Target ferritin level: >100 ng/mL 2

Evidence Analysis

The decision against IV iron in this case is supported by multiple guidelines:

• IV iron is primarily indicated for patients with:

  • Anemia (Hb <12 g/dL in females, <13 g/dL in males) 2
  • Intolerance to oral iron 2
  • Malabsorption conditions 1
  • Chronic inflammatory diseases (IBD, CKD, heart failure) 2
  • Ongoing blood loss 1

• The FDA label for IV iron (ferric carboxymaltose) indicates use for iron deficiency anemia, not non-anemic iron deficiency 4

• Clinical trials of IV iron primarily focused on patients with anemia (Hb <12 g/dL) 4

Important Considerations

• Investigate the cause of iron deficiency even with normal hemoglobin (gastrointestinal bleeding, menstrual blood loss, malabsorption, inadequate dietary intake) 1

• Potential pitfalls:

  • Overtreatment with IV iron can lead to iron overload and associated complications 3
  • Unnecessary IV iron administration exposes patients to risks (hypersensitivity reactions, cost) without clear benefit when oral iron is appropriate

• Special circumstances where IV iron might be considered despite normal hemoglobin:

  • Documented malabsorption disorders
  • Severe intolerance to oral iron
  • Chronic inflammatory conditions where oral iron absorption is impaired

In this specific case, with normal hemoglobin and mildly decreased ferritin, oral iron supplementation is the appropriate first-line therapy, with IV iron reserved only if oral therapy fails or is contraindicated.