What is the treatment for iron deficiency anemia with low ferritin and elevated UIBC?

Treatment for Iron Deficiency with Ferritin 5.21 and UIBC 364

You have absolute iron deficiency and require iron replacement therapy, with oral iron as first-line treatment unless you have contraindications such as inflammatory bowel disease, malabsorption, intolerance to oral iron, or ongoing blood loss—in which case intravenous iron is indicated.

Diagnostic Interpretation

Your laboratory values confirm absolute iron deficiency:

• Ferritin 5.21 ng/mL is severely depleted, well below the diagnostic threshold of <30 ng/mL for iron deficiency in patients without inflammation 1, 2
• UIBC 364 mcg/dL is elevated, indicating your body is attempting to bind more iron due to depleted stores 1
• This combination indicates absolute iron deficiency rather than functional iron deficiency or anemia of chronic disease 1

In the absence of inflammation, ferritin <30 ng/mL definitively establishes iron deficiency 1. Your ferritin of 5.21 ng/mL represents severe depletion of iron stores 2.

First-Line Treatment: Oral Iron

Oral ferrous sulfate 325 mg daily (or on alternate days) is the recommended initial therapy 2:

• Optimal dosing is 3-6 mg/kg of elemental iron per day 3
• Alternate-day dosing may improve tolerability while maintaining efficacy 2
• Treatment should continue for 3-6 months after hemoglobin normalizes to replenish iron stores 4

Monitor response at one month: You should see a 1-2 g/dL increase in hemoglobin 5. If this response does not occur, consider malabsorption, continued blood loss, or need for intravenous iron 1, 5.

When Intravenous Iron is Indicated

Switch to intravenous iron if you have 2:

• Oral iron intolerance or side effects
• Malabsorption conditions (celiac disease, inflammatory bowel disease, post-bariatric surgery)
• Chronic inflammatory conditions (chronic kidney disease, heart failure, inflammatory bowel disease, cancer)
• Ongoing blood loss that cannot be controlled
• Pregnancy (second or third trimester)

In inflammatory bowel disease specifically, intravenous iron is more effective, shows faster response, and is better tolerated than oral iron 1. For patients with heart failure and ferritin <100 ng/mL, intravenous iron (particularly ferric carboxymaltose) improves functional capacity and quality of life 1.

Critical Next Steps: Identify the Cause

You must undergo evaluation to identify the source of iron deficiency 2, 4:

• Gastrointestinal evaluation: Colonoscopy is recommended, especially if you are over age 50, as 9% of patients over 65 with iron deficiency have gastrointestinal cancer 5
• Menstrual history: Heavy menstrual bleeding is the most common cause in premenopausal women, affecting 38% with iron deficiency 2
• Dietary assessment: Inadequate iron intake, particularly in vegetarians 2
• Medication review: NSAIDs can cause occult gastrointestinal bleeding 2
• Malabsorption screening: Consider celiac disease, atrophic gastritis, or history of bariatric surgery 2, 4

Common Pitfalls to Avoid

Do not assume oral iron failure means true non-response: Up to 65% of patients who fail oral iron will respond to intravenous iron due to inflammation-mediated impaired absorption via hepcidin upregulation 1. If oral iron fails after 4 weeks, trial intravenous iron before concluding treatment failure 1.

Do not stop iron therapy when hemoglobin normalizes: Continue treatment for 3-6 months to replenish iron stores and prevent rapid recurrence 1, 4.

Do not overlook ongoing blood loss: If ferritin drops rapidly after initial correction, suspect continued bleeding or subclinical inflammatory activity requiring further investigation 1.