What is the recommended treatment for a patient with iron deficiency anemia, as indicated by low iron saturation and ferritin levels, with a Total Iron Binding Capacity (TIBC) of 390, Unsaturated Iron Binding Capacity (UIBC) of 343, Iron level of 47, Iron saturation of 12%, and Ferritin level of 33?

Treatment of Iron Deficiency Anemia

Start oral iron supplementation immediately with ferrous sulfate 325 mg daily (or on alternate days for better tolerance), as your iron panel confirms absolute iron deficiency anemia with ferritin 33 ng/mL and iron saturation 12%. 1

Diagnosis Confirmation

Your iron studies definitively show absolute iron deficiency:

• Ferritin 33 ng/mL (below the 45 ng/mL threshold, and well below the 30 ng/mL cutoff used in non-inflammatory states) 1
• Iron saturation 12% (significantly below the 20% threshold) 1
• TIBC 390 and UIBC 343 (elevated, consistent with iron deficiency) 1

This pattern indicates depleted iron stores requiring replacement therapy. 1

First-Line Treatment: Oral Iron

Initiate ferrous sulfate 325 mg once daily (containing 65 mg elemental iron), which provides 362% of the recommended daily intake. 2, 3

Dosing Strategy:

• Standard approach: 325 mg daily on an empty stomach for optimal absorption 1
• Alternate-day dosing: If gastrointestinal side effects occur (nausea, constipation, abdominal pain), switch to every-other-day dosing, which maintains efficacy while improving tolerance 1, 3
• With food: If empty-stomach dosing is intolerable, take with meals (preferably with meat protein), though absorption decreases 1
• Add vitamin C 500 mg with each dose to enhance absorption, especially if taking with food 1

Treatment Duration:

• Continue for 3 months after hemoglobin normalizes to replenish iron stores 1, 4
• Expect hemoglobin rise ≥10 g/L within 2 weeks if responding appropriately 1

When to Consider Intravenous Iron

Switch to IV iron if any of the following apply: 1

• Oral iron intolerance (persistent gastrointestinal side effects despite alternate-day dosing)
• No hemoglobin response after 4 weeks of adequate oral therapy
• Malabsorption conditions (celiac disease, post-bariatric surgery, atrophic gastritis)
• Ongoing blood loss that exceeds oral replacement capacity
• Chronic inflammatory conditions (inflammatory bowel disease, chronic kidney disease, heart failure)
• Pregnancy (second or third trimester with moderate-severe anemia) 1, 3

IV iron formulations include iron dextran, iron sucrose, ferric gluconate, or ferric carboxymaltose, typically given as 1000 mg total dose divided over 1-2 infusions. 1

Mandatory Evaluation for Underlying Cause

All adults with iron deficiency require investigation for the source of iron loss, as this is not normal even with dietary insufficiency alone: 1

For Men and Postmenopausal Women:

• Bidirectional endoscopy (upper endoscopy AND colonoscopy) is mandatory to exclude gastrointestinal malignancy and other bleeding sources 1
• Celiac serology (tissue transglutaminase antibody) before starting iron, as celiac disease causes malabsorption 1

For Premenopausal Women:

• Assess menstrual blood loss (heavy periods are the most common cause) 1, 4
• Consider gastrointestinal evaluation if menstrual losses don't fully explain the deficiency, especially if hemoglobin <100 g/L or if not responding to oral iron 1
• Screen for celiac disease 1

Additional Considerations:

• Review medications: NSAIDs, anticoagulants, antiplatelet agents cause occult GI bleeding 3, 5
• Dietary assessment: Vegetarian/vegan diets, inadequate intake 3, 4
• H. pylori testing: Can cause iron malabsorption and chronic gastritis 1

Monitoring Response

• Recheck complete blood count in 2-4 weeks: Expect hemoglobin rise ≥10 g/L if treatment is effective 1
• Repeat iron studies after 3 months of treatment to confirm store repletion (target ferritin >50 ng/mL) 1, 5
• Long-term monitoring: Check hemoglobin and ferritin every 3 months for the first year, then annually 1
• If no response to oral iron: This suggests either non-compliance, ongoing blood loss, malabsorption, or incorrect diagnosis—proceed to IV iron and intensify investigation 1

Critical Pitfalls to Avoid

• Do not skip the underlying cause evaluation: Iron deficiency in adults always warrants investigation, even if dietary intake seems inadequate 1, 4
• Do not use ferritin alone in inflammatory states: If concurrent inflammation suspected (elevated CRP), ferritin up to 100 ng/mL may still represent iron deficiency—use transferrin saturation <20% as confirmatory 1
• Do not transfuse for stable iron deficiency anemia: Red blood cell transfusions are rarely indicated for hemodynamically stable patients regardless of hemoglobin level 6
• Do not continue ineffective oral iron indefinitely: If no response after 4 weeks, switch to IV iron rather than prolonging oral therapy 1, 3