What is the diagnosis and management plan for a 64-year-old male with mild anemia, low iron, low ferritin, elevated TIBC, and normal vitamin B12 and folate levels?

Laboratory Interpretation and Diagnosis

This 64-year-old male has iron deficiency anemia (IDA) based on the classic laboratory pattern of low ferritin (16 ng/mL), low serum iron (35 μg/dL), elevated TIBC (385 μg/dL), and microcytic anemia (MCH 24.7, MCHC 30.8). 1

Key Laboratory Findings Supporting IDA

• Ferritin <30 μg/L is diagnostic of iron deficiency in the absence of inflammation 1
• Elevated TIBC (385 μg/dL) and transferrin (309 mg/dL) indicate the body's compensatory response to iron deficiency 2
• Transferrin saturation is approximately 9% (calculated as serum iron 35/TIBC 385 × 100), which is well below the 16% threshold confirming iron-deficient erythropoiesis 2
• Microcytic indices (MCH 24.7, MCHC 30.8) are characteristic of iron deficiency 1
• Normal ESR (10) and low reticulocyte count (0.7%) suggest this is not anemia of chronic disease and indicates inadequate bone marrow response to anemia 1
• Normal B12 (501) and folate (18.1) exclude nutritional macrocytic anemias 1

The elevated RDW (15.8) reflects the heterogeneous red cell population typical of iron deficiency 1.

Critical Management Priority: Identify the Source of Blood Loss

In a 64-year-old male with IDA, gastrointestinal malignancy must be excluded through endoscopic evaluation. 1, 3

Mandatory Workup

• Upper and lower gastrointestinal endoscopy is the standard of care for adult men with IDA, as asymptomatic colonic and gastric carcinoma commonly present this way 1, 3
• Do not attribute IDA to dietary insufficiency alone without complete GI investigation, even if dietary history suggests poor intake 1
• Document NSAID and aspirin use and discontinue if possible, as these are common causes of occult GI bleeding 1

Common GI Sources to Consider

• Colonic cancer/polyps, angiodysplasia (especially in elderly), gastric cancer, peptic ulcer disease, and esophagitis 1
• Angiodysplasia of the colon is particularly common in elderly patients and readily treatable endoscopically 4

Iron Replacement Therapy

Initiate oral iron supplementation immediately while pursuing diagnostic workup. 1, 5

Oral Iron Protocol

• Start with ferrous sulfate 324 mg (65 mg elemental iron) once daily 6, 3
• Lower-dose formulations (65 mg elemental iron daily) are as effective as higher doses and have fewer gastrointestinal side effects 3
• Expect hemoglobin normalization by 8 weeks in most patients who respond to oral therapy 3, 5
• Reticulocyte count should rise within 3-5 days if responding appropriately 2

When to Consider IV Iron

Switch to intravenous iron if: 1

• Patient is intolerant to oral iron (nausea, constipation, diarrhea)
• Inadequate hemoglobin response after 3-4 weeks of oral therapy
• Hemoglobin <10 g/dL with significant symptoms 1

IV iron delivers faster response rates and is safer than previously thought, though oral iron is appropriate for mild anemia (Hb >10 g/dL) 1

Monitoring and Follow-up

• Recheck CBC and iron parameters at 4-8 weeks after initiating treatment 2
• If no response to oral iron after 3 weeks, consider bone marrow aspiration or therapeutic trial to confirm true iron deficiency 1
• Continue iron supplementation for 3-6 months after hemoglobin normalizes to replenish iron stores 5

Important Caveats

Do not delay endoscopic evaluation while treating with iron supplementation—these should proceed in parallel 1, 3. The low reticulocyte count (0.7%) indicates the bone marrow is not responding appropriately to anemia, which should improve with iron repletion but warrants monitoring 1. If the patient fails to respond to adequate iron replacement, consider referral to hematology for evaluation of other causes such as myelodysplastic syndrome, particularly given his age 1, 7.