What is the appropriate management for an adult patient with hypoferritinemia and elevated Total Iron-Binding Capacity (TIBC), indicating iron deficiency anemia?

Iron Deficiency Anemia Management

Immediate Interpretation

Your laboratory values (serum iron 17 µg/dL, TIBC 243 µg/dL) indicate iron deficiency with a transferrin saturation of 7%, which is well below the diagnostic threshold of 16% for iron deficiency in adults. 1

Diagnostic Confirmation

Your transferrin saturation calculation confirms absolute iron deficiency:

• Transferrin saturation = (17/243) × 100 = 7%
• This is significantly below the 16% cutoff used to confirm iron deficiency 1
• The elevated TIBC (243 µg/dL) reflects increased iron-binding capacity when iron stores are depleted 1

You should obtain a serum ferritin level immediately to complete the iron deficiency assessment, as ferritin is the most specific test for iron deficiency in the absence of inflammation 1

Treatment Initiation

Start oral iron supplementation immediately without waiting for additional test results or investigation completion. 2

• Ferrous sulfate 324 mg daily (containing 65 mg elemental iron) is the recommended first-line choice 2, 3
• Alternative dosing: 100-200 mg elemental iron daily in divided doses 2
• Take on an empty stomach when possible to maximize absorption, though taking with food is acceptable if gastrointestinal side effects occur 4

Investigation for Underlying Cause

The approach to investigation depends critically on your demographic profile:

For Men or Postmenopausal Women:

Bidirectional endoscopy (gastroscopy and colonoscopy) should be performed as first-line GI investigation to exclude gastrointestinal malignancy and other pathology 1, 2

• Do not delay investigation pending response to iron therapy, as this may miss GI malignancy 2
• Screen for celiac disease with serology, as it is found in 3-5% of IDA cases 1, 2
• Perform urinalysis to exclude urinary blood loss 1

For Premenopausal Women:

• GI investigation is generally not warranted in the absence of GI symptoms, family history of GI pathology, or other concerning features, as menstrual blood loss and/or recent pregnancy are the likely causes 1
• However, the threshold for investigation should be low if GI symptoms are present 1
• Screen for celiac disease regardless 1

Monitoring Response

Reassess hemoglobin after 2-4 weeks of iron therapy:

• An expected response is Hb rise ≥10 g/L within 2 weeks, which is highly suggestive of absolute iron deficiency 2
• Repeat complete iron studies (including ferritin) after 8-10 weeks to measure treatment success 4

When to Consider Intravenous Iron

Intravenous iron is indicated over oral iron in the following situations: 2

• Intolerance to oral iron (gastrointestinal side effects)
• Malabsorption conditions (celiac disease, inflammatory bowel disease, prior gastric surgery)
• Ongoing blood loss exceeding intestinal absorption capacity
• Chronic inflammatory conditions where oral iron is poorly absorbed
• Need for rapid iron replenishment

Critical Pitfalls to Avoid

• Do not assume dietary deficiency alone without excluding pathologic causes, especially in men and postmenopausal women 2
• Do not interpret a "normal" ferritin as excluding iron deficiency if inflammation is present, as ferritin is an acute phase reactant 1
• Do not use ferritin >150 µg/L as a cutoff, as absolute iron deficiency is unlikely above this level even with inflammation 1
• Do not delay treatment while pursuing diagnostic workup - start oral iron immediately 2