What is the best initial treatment for a patient with iron deficiency anemia, characterized by low hemoglobin, low iron, elevated Total Iron Binding Capacity (TIBC), low iron saturation, and ferritin level of 87.7?

Iron Deficiency Anemia: Initial Treatment Approach

Start oral iron supplementation immediately with ferrous sulfate 325 mg daily (or on alternate days) as first-line therapy for this patient with confirmed iron deficiency anemia. 1, 2

Diagnostic Interpretation

Your patient's laboratory values confirm absolute iron deficiency anemia:

• Hemoglobin 8.3 g/dL: Severe anemia (WHO defines anemia as <13 g/dL in men, <12 g/dL in non-pregnant women) 1
• Iron saturation 11.5%: Markedly low (normal >20%) 1
• Ferritin 87.7 ng/mL: While seemingly "normal," this is actually consistent with iron deficiency in the context of low transferrin saturation. Ferritin <100 ng/mL with TSAT <20% indicates true iron deficiency 1
• Elevated TIBC 246: Consistent with iron deficiency 1

The British Society of Gastroenterology guidelines emphasize that ferritin <45 μg/L has 92% specificity for iron deficiency, but ferritin can be falsely elevated by inflammation. Your patient's constellation of findings—low iron saturation, elevated TIBC, and ferritin <100 ng/mL—definitively confirms iron deficiency. 1

Immediate Treatment Plan

Oral Iron Therapy (First-Line)

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

• Recent evidence supports alternate-day dosing (325 mg every other day) for better absorption and fewer gastrointestinal side effects 1, 2
• Typical oral iron doses range 100-200 mg elemental iron daily in divided doses 1
• Avoid taking with food, calcium, or proton pump inhibitors which impair absorption 1

When to Consider Intravenous Iron

IV iron is indicated if: 2, 4

• Oral iron intolerance (constipation, nausea, diarrhea occur commonly)
• Ongoing blood loss exceeding intestinal absorption capacity
• Malabsorption conditions (celiac disease, post-bariatric surgery, inflammatory bowel disease)
• Chronic inflammatory conditions (CKD, heart failure, cancer)
• Need for rapid iron repletion

Available IV formulations include iron sucrose, ferric carboxymaltose, ferumoxytol, and low molecular weight iron dextran. Ferric carboxymaltose allows rapid administration of large single doses (up to 1000 mg over 15 minutes) with very low risk (<1:250,000) of serious reactions. 1

Critical Next Steps: Identify the Source

This degree of anemia (Hgb 8.3 g/dL) mandates urgent investigation for underlying pathology, particularly gastrointestinal bleeding or malignancy. 1

Required Workup:

• Gastrointestinal evaluation: Men with any degree of anemia and iron deficiency, or women with Hgb <10 g/dL should undergo bidirectional endoscopy (upper and lower GI) to exclude malignancy 1
• Stool guaiac testing for occult blood 1
• Celiac serology (tissue transglutaminase antibody) - approximately 5% of IDA patients have celiac disease 1
• Medication review: NSAIDs are common culprits and should be discontinued if possible 1
• Menstrual history in premenopausal women (38% have iron deficiency, 13% have IDA) 2

Additional Laboratory Tests:

• Renal function (creatinine, GFR) to assess for chronic kidney disease 1
• Thyroid function tests 1
• Vitamin B12 and folate if macrocytosis present 1
• Hemoglobin electrophoresis if microcytosis disproportionate to anemia (suggests thalassemia) 1

Monitoring Response to Treatment

Recheck hemoglobin and iron studies after 8-10 weeks of oral iron therapy—not earlier, as ferritin levels remain falsely elevated immediately after iron supplementation. 1

Expected response to adequate iron therapy: 4, 5

• Reticulocyte count increases within 5-10 days
• Hemoglobin rises by approximately 1-2 g/dL within 3-4 weeks
• Complete correction typically requires 2-3 months

If no response after 4-6 weeks of oral iron: 1

• Consider trial of IV iron (65% response rate vs 21% with continued oral iron in non-responders) 1
• Reassess for ongoing blood loss
• Evaluate for malabsorption
• Check compliance and medication interactions

Common Pitfalls to Avoid

• Don't assume ferritin >30 ng/mL excludes iron deficiency—in inflammatory states, ferritin up to 100 ng/mL may still represent true deficiency 1
• Don't delay investigation in men or postmenopausal women—GI malignancy must be excluded 1, 2
• Don't continue oral iron indefinitely without response—switch to IV iron after 4-6 weeks of non-response 1
• Don't overlook dual pathology—1-10% of patients have bleeding sources in both upper and lower GI tracts 1