What is the treatment for a patient with a ferritin level indicating iron deficiency?

Treatment for Iron Deficiency with Ferritin Level of 15 μg/L

Oral iron supplementation is the first-line treatment for patients with a ferritin level of 15 μg/L indicating iron deficiency, with a recommended dose of 60-200 mg elemental iron daily. 1

Diagnosis Confirmation

A ferritin level of 15 μg/L clearly indicates iron deficiency, as it falls below the diagnostic threshold of:

• <30 μg/L for adults (>15 years) 1
• <20 μg/L for adolescents (12-15 years)
• <15 μg/L for children (6-12 years)

Additional laboratory tests to complete the iron deficiency workup include:

• Transferrin saturation (should be <16%)
• Hemoglobin and hematocrit (to determine if anemia is present)
• C-reactive protein (to exclude inflammatory conditions that may affect ferritin interpretation) 1, 2

Treatment Algorithm

Step 1: Oral Iron Therapy

• First-line treatment: Oral iron supplementation 1, 3
  • Ferrous sulfate 325 mg daily or on alternate days (provides 60-65 mg elemental iron)
  • Reasonable elemental iron content (28-50 mg) is appropriate to minimize side effects 2
  • Take on an empty stomach if tolerated
  • Add vitamin C (250-500 mg) with iron to enhance absorption 1

Step 2: Dietary Modifications

• Increase intake of iron-rich foods:
  • Heme iron sources: red meat, poultry, fish
  • Non-heme iron sources: dark leafy greens, legumes, nuts, seeds
• Avoid iron absorption inhibitors with meals:
  • Tea, coffee, calcium supplements
  • Certain antacids or proton pump inhibitors 1

Step 3: Monitoring Response

• Repeat hemoglobin and iron studies after 4 weeks of treatment 1
• Continue iron therapy for 3 months after correction of anemia to replenish iron stores
• Target parameters:
  • Serum ferritin >100 ng/mL
  • Transferrin saturation >20%
  • Hemoglobin 11-12 g/dL 1

Step 4: Consider Intravenous Iron if:

• Intolerance to at least two oral preparations
• Non-compliance with oral therapy
• Malabsorption conditions
• Need for rapid iron repletion
• Ongoing blood loss
• Chronic inflammatory conditions (IBD, CKD, heart failure) 1, 3

Evaluation of Underlying Causes

It's essential to identify and address the cause of iron deficiency:

• For menstruating women: Assess menstrual blood loss
• For all patients: Consider gastrointestinal blood loss
  • When absolute iron deficiency is detected, referral to a gastroenterologist is indicated to rule out gastrointestinal malignancy 4
• Screen for celiac disease with tissue transglutaminase antibody 1
• Assess dietary intake and absorption issues
• Consider pregnancy status in women of childbearing age 3

Important Considerations and Pitfalls

• Warning: Do not exceed recommended dosage as iron overdose can be fatal, especially in children 5
• Side effects: Oral iron may cause gastrointestinal discomfort, black stools, constipation, or diarrhea 5
  • Taking with meals may minimize GI discomfort but reduces absorption
• Drug interactions: Oral iron interferes with tetracycline antibiotics absorption; separate administration by at least 2 hours 5
• Pitfall: Using outdated ferritin cutoffs may lead to underdiagnosis of iron deficiency
  • Some evidence suggests a physiologic ferritin cutoff of 50 μg/L 6
  • In inflammatory conditions, ferritin levels up to 100 μg/L may still indicate iron deficiency 7
• Caution: Long-term daily oral or intravenous iron supplementation in the presence of normal or high ferritin values is not recommended and potentially harmful 2

By following this algorithm, iron deficiency can be effectively treated while investigating and addressing the underlying cause.