What is the treatment for low ferritin levels?

Treatment of Low Ferritin

For symptomatic patients with low ferritin, oral iron supplementation with ferrous sulfate 100-200 mg elemental iron daily (or on alternate days to reduce side effects) is first-line therapy, with intravenous iron reserved for specific situations including oral intolerance, malabsorption, ongoing blood loss, chronic inflammatory conditions, or pregnancy. 1, 2

Diagnostic Thresholds

Before initiating treatment, confirm iron deficiency with appropriate testing:

• Ferritin <30 µg/L indicates iron deficiency in healthy adults without inflammation 1, 3, 2
• Ferritin <40 ng/mL is an alternative threshold used in symptomatic patients 4
• For children 6-12 years: ferritin <15 µg/L 3
• For adolescents 12-15 years: ferritin <20 µg/L 3
• Transferrin saturation <20% provides additional diagnostic confirmation, particularly when inflammation may falsely elevate ferritin 1, 2

Important caveat: Ferritin is an acute phase reactant and can be falsely elevated during inflammation. Always exclude acute inflammation by checking C-reactive protein before interpreting ferritin levels. 3

Oral Iron Supplementation (First-Line)

Dosing:

• 100-200 mg elemental iron daily in divided doses 1
• Ferrous sulfate 324 mg tablets contain 65 mg elemental iron 5
• Alternate-day dosing (rather than daily) may improve absorption and reduce gastrointestinal side effects 1, 2
• Preparations with 28-50 mg elemental iron content are appropriate to minimize side effects while maintaining efficacy 3

Administration guidelines:

• Co-ingest with vitamin C to enhance absorption of non-heme iron 1
• Avoid tea and coffee around meal times as they impair iron absorption 1
• Integrate heme iron sources (red meat, seafood) into diet for better bioavailability 1

Monitoring:

• Repeat ferritin and hemoglobin after 8-10 weeks to assess treatment response 1, 3
• Do not check ferritin earlier after IV iron as levels will be falsely elevated 1

Intravenous Iron (Second-Line or Specific Indications)

Indications for IV iron: 1, 2, 6

• Oral iron intolerance or gastrointestinal side effects
• Impaired iron absorption (celiac disease, atrophic gastritis, post-bariatric surgery)
• Ongoing blood loss requiring rapid iron replacement
• Chronic inflammatory conditions (CKD, heart failure, IBD, cancer)
• Second and third trimesters of pregnancy
• Failure of oral iron therapy after adequate trial

Dosing considerations:

• Multiple formulations available (ferric carboxymaltose, iron sucrose, ferric gluconate, low molecular weight iron dextran) 1
• Ferric carboxymaltose allows rapid administration of large single doses over 15 minutes 1
• Risk minimization: Reactions are rare (<1:250,000) but can be life-threatening; highest risk with high molecular weight iron dextran 1

Special populations:

• In critically ill patients with inflammation, hepcidin is a more reliable indicator of iron deficiency than transferrin saturation 1
• In CKD patients on erythropoiesis-stimulating agents (ESAs), target ferritin >200 ng/mL and transferrin saturation >20% for optimal response 1

Safety Considerations

Avoid iron supplementation when: 1

• Ferritin is normal or elevated (>500 µg/L) without functional iron deficiency
• No symptoms or anemia present
• Monitor ferritin levels and do not exceed 500 mg/L to avoid toxicity, especially in children and adolescents 1

Contraindications and precautions:

• Avoid vitamin C supplements in iron-loaded patients, particularly during phlebotomy for hemochromatosis 1
• Avoid iron-fortified foods when possible in patients with iron overload 1
• Long-term daily supplementation with normal/high ferritin is potentially harmful 3, 2

Treatment of Underlying Causes

Always identify and address the cause of iron deficiency: 2, 6

• Heavy menstrual bleeding (consider hormonal management)
• Gastrointestinal bleeding (endoscopic evaluation if indicated)
• Malabsorption disorders (treat celiac disease, H. pylori gastritis)
• Inadequate dietary intake (nutritional counseling)
• Pregnancy-related increased demand

Maintenance Therapy

For patients with recurrent iron deficiency:

• Intermittent oral supplementation to preserve iron stores 3
• Monitor ferritin every 6-12 months in high-risk patients 3
• Continue addressing underlying causes (e.g., menstrual blood loss reduction)

Common pitfall: Do not continue iron supplementation indefinitely without monitoring ferritin levels, as this can lead to iron overload and potential toxicity. 1, 3