Diagnosis: Iron Deficiency Anemia
This 54-year-old female has iron deficiency anemia, and the first-line treatment is oral ferrous sulfate 324 mg (65 mg elemental iron) one to three times daily for at least three months after hemoglobin normalizes to replenish iron stores. 1, 2
Diagnostic Confirmation
The laboratory findings definitively indicate iron deficiency anemia:
Microcytic hypochromic pattern: MCV 70 fL (normal 80-100), MCH 20.0 pg (normal 27-31), and MCHC 28.6 g/dL (normal 32-36) are all markedly reduced, characteristic of iron deficiency 1, 2
Elevated RDW: RDW 16.7% (>14.0%) combined with low MCV strongly distinguishes iron deficiency anemia from thalassemia minor, which typically presents with RDW ≤14.0% 1, 2
Severity assessment: Hemoglobin 9.3 g/dL and hematocrit 32.5% represent moderate anemia requiring treatment 2
While serum ferritin is the gold standard confirmatory test (with <45 μg/L providing optimal sensitivity and specificity for iron deficiency), the clinical picture here is unambiguous 1, 2. Additional iron studies (serum iron, TIBC, transferrin saturation) would show low serum iron, elevated TIBC, and low transferrin saturation (<16-20%) if obtained 2, 3.
Treatment Protocol
Oral iron supplementation:
Ferrous sulfate 324 mg (65 mg elemental iron) one to three times daily is the first-line treatment 1, 2
Duration: Continue for at least three months after hemoglobin normalizes to fully replenish iron stores 1, 2
Alternative formulations: If gastrointestinal side effects occur (nausea, constipation, abdominal discomfort), switch to ferrous gluconate or ferrous fumarate 1, 2
Absorption enhancement: Adding ascorbic acid (vitamin C) 200-500 mg with each iron dose enhances absorption 1, 2
Expected Response and Monitoring
Response timeline:
Within 2 weeks: Hemoglobin should rise ≥10 g/L (≥1 g/dL), confirming iron deficiency as the cause 1, 2
Within 4 weeks: Expect hemoglobin increase of at least 2 g/dL 1, 2
Monitoring schedule:
Check hemoglobin, hematocrit, MCV, and MCH at 2 weeks, 4 weeks, 3 months, then every 3 months for the first year, then annually 1, 2
Measure serum ferritin and transferrin saturation at 3 months to confirm iron store repletion 2, 4
Provide additional oral iron if hemoglobin or MCV falls below normal during follow-up 1, 4
Mandatory Investigation for Underlying Cause
Critical pitfall to avoid: Iron deficiency anemia in a 54-year-old female requires identification of the source of iron loss 1, 4
Investigate for:
Gastrointestinal blood loss: History of melena, hematochezia, occult bleeding, or gastrointestinal symptoms warrants endoscopy 1, 4
Menstrual blood loss: Heavy menstrual bleeding is the most common cause in premenopausal women, though at age 54 perimenopausal status should be assessed 1
Dietary inadequacy: Assess dietary iron intake, though this alone rarely causes severe deficiency 1
Malabsorption: Screen for celiac disease if malabsorption suspected (chronic diarrhea, weight loss, bloating) 1
Referral threshold: Non-menstruating women with hemoglobin <100 g/L (10 g/dL) warrant fast-track gastrointestinal referral to exclude malignancy 1, 4. This patient's hemoglobin of 9.3 g/dL meets this criterion.
When to Consider Intravenous Iron
Intravenous iron (iron sucrose or iron gluconate) should be considered if: 1, 2
- Malabsorption is documented
- Patient cannot tolerate oral iron despite trying alternative formulations
- Ongoing blood loss exceeds oral replacement capacity
- No hemoglobin response after 4 weeks of adequate oral therapy
Expected hemoglobin increase with IV iron is at least 2 g/dL within 4 weeks 1, 2
Differential Diagnosis Considerations
Genetic disorders are unlikely given the patient's age and presentation, but should be considered if: 5, 1
- Extreme microcytosis (MCV <60 fL) with family history
- Failure to respond to oral iron therapy
- Elevated ferritin with low transferrin saturation (suggests IRIDA/TMPRSS6 mutations)
- High transferrin saturation with microcytic anemia (suggests SLC11A2 defects)
Thalassemia trait is excluded by the elevated RDW (16.7%); thalassemia typically presents with RDW ≤14.0% and would require hemoglobin electrophoresis showing elevated hemoglobin A2 1, 3
Incidental Findings
- Glucose 108 mg/dL: Mildly elevated, suggesting impaired fasting glucose; recommend hemoglobin A1c and diabetes screening
- Alkaline phosphatase 151 U/L: Mildly elevated; may be physiologic or related to bone turnover, but monitor and consider liver function tests if persistent