Treatment Approach for Mild Microcytic Anemia
Start oral iron supplementation with ferrous sulfate 200 mg three times daily (providing approximately 65 mg elemental iron per tablet) for at least three months after hemoglobin normalizes to replenish iron stores. 1, 2
Confirm Iron Deficiency First
Before initiating treatment, you need to confirm this is iron deficiency anemia:
Order serum ferritin immediately - this is the single most powerful test for iron deficiency, with levels <15 μg/L indicating absent iron stores and <30 μg/L indicating low body iron stores. 3, 1 A cut-off of 45 μg/L provides optimal sensitivity and specificity in practice. 1, 2
Add transferrin saturation (TSAT) - this is more sensitive than hemoglobin alone for detecting iron deficiency. 1 A TSAT <30% supports the diagnosis. 3
The patient's lab findings show MCH 26.2 pg (low) and MCHC 31.1 g/dL (low) with RDW 14.1%, which is consistent with iron deficiency anemia rather than thalassemia trait (which typically has RDW ≤14.0%). 1, 2
Oral Iron Therapy Protocol
Prescribe ferrous sulfate 200 mg three times daily, taken separately from meals to maximize absorption. 1, 2
If ferrous sulfate is not tolerated due to gastrointestinal side effects, switch to ferrous gluconate or ferrous fumarate. 1
Add ascorbic acid (vitamin C) to enhance iron absorption. 1, 2
Continue treatment for at least three months after anemia correction to fully replenish iron stores. 1, 2
Expected Response and Monitoring
Hemoglobin should rise ≥10 g/L (≥1 g/dL) within 2 weeks - this confirms iron deficiency as the cause. 1, 2
Recheck complete blood count at 2-4 weeks to document response. 1
Monitor hemoglobin and red cell indices at three-monthly intervals for one year, then again after another year. 1
Provide additional oral iron if hemoglobin or MCV falls below normal during follow-up. 1
Critical: Investigate the Source of Iron Loss
In a 51-year-old woman with confirmed iron deficiency, you must investigate the underlying cause - iron deficiency is not a diagnosis, it's a finding that requires explanation. 3, 1
Evaluate for gastrointestinal blood loss through history of melena, hematochezia, or occult bleeding. Upper and lower GI endoscopy should be considered to exclude malignancy, especially if hemoglobin is significantly low. 3, 1
Assess menstrual blood loss - heavy menstrual bleeding is the most common cause in premenopausal women, though at age 51 she may be perimenopausal. 1
Screen for celiac disease if malabsorption is suspected, as this is a frequently missed cause. 3, 1
Review medications, particularly NSAIDs, which can cause occult GI bleeding. 3
Management of Treatment Failure
If the patient fails to respond to oral iron within 2-4 weeks (hemoglobin rise <2 g/dL):
Consider non-compliance, ongoing blood loss, malabsorption, or rare genetic disorders. 1
Switch to intravenous iron if malabsorption is present (expected hemoglobin increase of at least 2 g/dL within 4 weeks). 1, 2
Order hemoglobin electrophoresis if microcytosis persists with normal iron studies, as this suggests thalassemia trait rather than iron deficiency. 1, 2
Genetic testing for rare disorders (IRIDA, sideroblastic anemia) is only warranted if extreme microcytosis (MCV <70), family history, or complete refractoriness to both oral and IV iron. 3, 1
Common Pitfalls to Avoid
Do not assume all microcytic anemia is iron deficiency - anemia of chronic disease, thalassemia, and sideroblastic anemia must be differentiated to avoid unnecessary iron therapy. 1
Do not overlook combined deficiencies - iron deficiency can coexist with B12 or folate deficiency, which may mask microcytosis due to elevated RDW. 3, 2
Do not fail to investigate the source - treating the anemia without finding the cause risks missing gastrointestinal malignancy or other serious pathology. 3, 1
Monitor serum ferritin during treatment and do not exceed 500 μg/L to avoid iron overload toxicity. 2