Is it correct that a 72‑year‑old man with normal hemoglobin and low ferritin has absolute iron deficiency but is not anemic?

Assessment of Iron Status in a 72-Year-Old Man with Normal Hemoglobin and Low Ferritin

The statement is correct: this patient has absolute iron deficiency without anemia. 1, 2, 3

Defining Absolute Iron Deficiency

Absolute iron deficiency is characterized by depleted iron stores (low ferritin) regardless of whether anemia is present. 2, 3 The patient's ferritin of 17.7 μg/L falls well below the diagnostic threshold:

• Ferritin <30 μg/L indicates depleted body iron stores in patients without inflammation 1, 2
• Ferritin <15 μg/L has 99% specificity for absolute iron deficiency 1, 2
• This patient's value of 17.7 μg/L clearly meets criteria for absolute iron deficiency 1, 2

Distinguishing Iron Deficiency from Anemia

Iron deficiency and anemia are distinct conditions that often—but not always—coexist. 2, 3 The progression follows predictable stages:

• Stage 1 (Iron Depletion): Ferritin drops below 30 μg/L while hemoglobin remains normal 2, 3
• Stage 2 (Iron-Deficient Erythropoiesis): Transferrin saturation falls below 16-20%, MCV begins to decline, but hemoglobin may still be normal 1, 2
• Stage 3 (Iron-Deficiency Anemia): Hemoglobin drops below 13 g/dL in men or 12 g/dL in women 1, 3

This patient is in Stage 1 or early Stage 2—iron stores are depleted but hemoglobin production has not yet been compromised enough to cause anemia. 2, 3

Clinical Significance of Non-Anemic Iron Deficiency

Iron deficiency without anemia is clinically significant and warrants treatment. 1, 2, 3 Even before anemia develops, patients may experience:

• Fatigue and reduced exercise tolerance 2, 3
• Difficulty concentrating and irritability 3
• Restless legs syndrome (32-40% prevalence) 3
• Reduced aerobic performance 2

Diagnostic Confirmation and Next Steps

Calculate transferrin saturation to confirm iron-restricted erythropoiesis: 1, 2

• TSAT = (serum iron × 100) ÷ total iron-binding capacity 1
• TSAT <16-20% confirms iron deficiency 1, 2

In a 72-year-old man, absolute iron deficiency mandates investigation for gastrointestinal blood loss: 1, 2

• Screen for celiac disease with tissue transglutaminase antibodies (present in 3-5% of iron-deficiency cases) 1, 2
• Test for Helicobacter pylori non-invasively 1, 2
• Bidirectional endoscopy (upper and lower GI) is mandatory in older men because iron deficiency may be the sole manifestation of gastrointestinal malignancy 1, 2

Initiate oral iron supplementation immediately without waiting for investigation results: 1, 2, 3

• Ferrous sulfate 65 mg elemental iron daily (or alternate-day dosing to improve absorption and reduce side effects) 1, 2, 3
• Expected response: hemoglobin should rise ≥10 g/L within 2 weeks 2
• Continue for 3 months after hemoglobin normalizes to achieve ferritin >100 ng/mL 1, 2

Critical Pitfall to Avoid

Do not assume that normal hemoglobin excludes the need for iron supplementation or investigation. 1, 2, 3 Ferritin <30 μg/L indicates depleted iron stores that will eventually progress to anemia if the underlying cause is not identified and corrected. 1, 2, 3 In older adults, the yield of pathology on GI investigation is substantially higher than in younger populations, making endoscopic evaluation essential even when hemoglobin is normal. 1, 2