When should iron supplementation be started in patients with iron deficiency anemia?

Iron Supplementation for Iron Deficiency Anemia

Iron supplementation should be initiated immediately in all patients diagnosed with iron deficiency anemia to normalize hemoglobin levels and replenish iron stores. 1

Diagnostic Criteria for Iron Deficiency Anemia

Before starting treatment, confirm the diagnosis with:

• Serum ferritin:
  • <30 μg/L in patients without inflammation
  • <100 μg/L in patients with inflammation or chronic disease 1, 2
• Transferrin saturation <20% 2
• Complete blood count showing low hemoglobin (<12 g/dL in women, <13 g/dL in men)

Treatment Algorithm

First-Line Treatment Selection

1. Oral Iron Therapy - First-line for:

   • Mild anemia
   • Clinically inactive disease
   • No previous intolerance to oral iron 1

2. Intravenous Iron Therapy - First-line for:

   • Clinically active inflammatory disease
   • Previous intolerance to oral iron
   • Hemoglobin <10 g/dL (severe anemia)
   • Patients needing erythropoiesis-stimulating agents
   • Conditions with impaired oral iron absorption 1

Oral Iron Administration

• Dosage: 60-120 mg elemental iron daily 2
  • For symptom-free patients: 100 mg ferrous fumarate once daily
  • For severe anemia or symptomatic patients: 200 mg ferrous fumarate daily 3
  • If side effects occur: Consider alternate-day dosing 3
• Administration: Take in the morning with vitamin C to enhance absorption 2
• Duration: Continue for 3 months after hemoglobin normalization to replenish iron stores

Intravenous Iron Administration

• Dosing: Based on baseline hemoglobin and body weight
  • For Hb 10-12 g/dL (women) or 10-13 g/dL (men): 1000 mg if <70 kg; 1500 mg if >70 kg
  • For Hb 7-10 g/dL: 1500 mg if <70 kg; 2000 mg if >70 kg 1

Monitoring Response

1. Check hemoglobin after 3-4 weeks of treatment

   • Expected response: 1-2 g/dL increase within 4-8 weeks 2
   • An increase of at least 2 g/dL within 4 weeks is considered acceptable 1

2. For IV iron therapy:

   • Check CBC and iron studies 4-8 weeks after last infusion
   • Do not check iron studies within 4 weeks of IV iron (falsely elevated results) 2

3. Target values:

   • Ferritin ≥100 μg/L
   • Hemoglobin 12-13 g/dL (gender-specific) 1, 2

4. After successful treatment:

   • Re-treatment should be initiated when ferritin drops below 100 μg/L or
   • Hemoglobin falls below gender-specific thresholds (12 g/dL for women, 13 g/dL for men) 1

Common Pitfalls to Avoid

1. Delayed treatment initiation - Iron deficiency anemia impacts quality of life and should be treated promptly 1

2. Inadequate dosing - Underdosing oral iron is common; ensure adequate elemental iron content

3. Premature discontinuation - Continue treatment until both hemoglobin normalizes AND iron stores are replenished

4. Overlooking the underlying cause - Always investigate the etiology of iron deficiency, especially in men and postmenopausal women

5. Inappropriate parenteral iron use - Reserve for specific indications; unnecessary IV iron increases costs and risks

6. Inadequate monitoring - Regular follow-up is essential to confirm response and adjust therapy

7. Ignoring inflammation - In inflammatory conditions, standard ferritin cutoffs may miss iron deficiency; use higher thresholds (up to 100 μg/L) 1, 2

By following this structured approach to iron supplementation in iron deficiency anemia, clinicians can effectively restore hemoglobin levels and iron stores while minimizing complications and improving patient outcomes.