What is the best course of action for a patient with iron deficiency anemia, currently on iron supplementation, with fluctuating ferritin levels, low iron saturation, and normal hemoglobin levels?

Management of Iron Deficiency with Normal Hemoglobin

Continue iron supplementation until ferritin reaches at least 100 ng/mL, then monitor every 3 months for the first year to prevent recurrence. 1

Current Clinical Status Assessment

Your patient presents with:

• Normal hemoglobin (14.2 g/dL) - above anemia threshold 1
• Severe iron deficiency - iron saturation 12.92% (normal >20%) and fluctuating ferritin (10-585 ng/mL) 1, 2
• Already on iron supplementation

This represents iron deficiency without anemia, which still requires treatment because iron is essential for cellular function beyond oxygen transport, affecting cognitive performance, physical capacity, and quality of life. 3, 2

Treatment Strategy

Continue Iron Supplementation

The goal is to normalize iron stores, not just hemoglobin. 1 Your patient's hemoglobin has corrected, but iron stores remain depleted based on the low saturation and history of ferritin dropping to 10 ng/mL.

• Continue supplementation for 3 months after hemoglobin normalization to replenish body stores 1
• Target ferritin >100 ng/mL before considering stopping therapy 1
• The low iron saturation (12.92%) indicates functional iron deficiency despite the ferritin fluctuation to 585 ng/mL 1, 2

Route of Administration Decision

Oral iron is appropriate if:

• Disease is clinically inactive (no GI symptoms) 1
• Patient tolerates current oral regimen 1
• Hemoglobin >100 g/L (10 g/dL) - which this patient meets 1

Consider switching to intravenous iron if:

• Patient has underlying inflammatory conditions (IBD, CKD, HF) that may falsely elevate ferritin 1, 2
• Oral iron intolerance develops 1, 2
• Ongoing blood loss is present 2
• Malabsorption suspected (celiac disease, post-bariatric surgery) 2

The ferritin fluctuation from 10 to 585 ng/mL is concerning - ferritin is an acute phase reactant and can be falsely elevated during inflammation even when true iron deficiency exists. 1 This explains why saturation remains low (12.92%) despite ferritin reaching 585 ng/mL.

Oral Iron Dosing

If continuing oral therapy:

• Ferrous sulfate 325 mg daily or alternate-day dosing 2
• Maximum 100 mg elemental iron per day in IBD patients (if applicable) 1
• Consider ascorbic acid if response is poor 1
• Lower doses (28-50 mg elemental iron) may improve compliance by reducing GI side effects 3

Monitoring Protocol

Short-term (Next 8-10 weeks)

• Repeat complete iron panel (hemoglobin, ferritin, iron saturation, transferrin saturation) 3
• Assess response: hemoglobin should rise 2 g/dL after 3-4 weeks if anemia recurs 1
• Check C-reactive protein to exclude inflammation falsely elevating ferritin 3

Long-term Surveillance

• Monitor every 3 months for the first year after correction 1
• Then every 6-12 months thereafter 1
• Reinitiate treatment when:
  • Ferritin drops below 100 ng/mL 1
  • Hemoglobin falls below 12-13 g/dL (gender-dependent) 1
  • Iron saturation remains <20% 2

Investigation for Underlying Cause

Identify and treat the source of iron loss: 1

• Test for H. pylori and celiac disease (non-invasive testing first) 1
• Consider bidirectional endoscopy if:
  • Male or postmenopausal female (strong recommendation) 1
  • GI symptoms present 1
  • Premenopausal women with recurrent deficiency despite supplementation 1
• Evaluate for menorrhagia in premenopausal women 1
• Review medications: NSAIDs, anticoagulants, antiplatelet agents 1, 2
• Screen for inflammatory conditions: IBD, CKD, heart failure 1, 2

Common Pitfalls

Do not stop iron supplementation when hemoglobin normalizes - this is the most common error. Iron stores require 3 additional months of therapy after anemia correction. 1

Do not rely on ferritin alone when inflammation is present - the saturation of 12.92% is the more reliable indicator of true iron deficiency in this case. 1

Recurrent iron deficiency may indicate subclinical disease activity even when inflammatory markers appear normal, particularly in IBD patients. 1

Failure to respond suggests: non-compliance, continued blood loss, malabsorption, or misdiagnosis. 1