What is the management approach for a patient with microcytosis (MCV of 68)?

Management of Microcytosis (MCV 68)

For a patient with significant microcytosis (MCV of 68), a comprehensive workup for iron deficiency anemia and thalassemia trait should be initiated, with serum ferritin as the first-line diagnostic test. 1, 2

Diagnostic Approach

Initial Laboratory Testing

• Serum ferritin - First recommended test for microcytosis evaluation 2

  • Low ferritin (<30 μg/L) indicates iron deficiency
  • Normal/high ferritin suggests alternative diagnosis

• Additional tests if ferritin is not low:

  • Complete blood count with RBC count and RDW
  • Serum iron
  • Total iron-binding capacity (TIBC)
  • Transferrin saturation
  • Hemoglobin electrophoresis (especially if suspecting thalassemia)

Differential Diagnosis Based on Laboratory Parameters

Parameter	Iron Deficiency	Thalassemia Trait	Anemia of Chronic Disease
MCV	Low	Very low (<70 fl)	Low/Normal
RDW	High (>14%)	Normal (≤14%)	Normal/Slightly elevated
Ferritin	Low (<30 μg/L)	Normal	Normal/High
TSAT	Low	Normal	Low
RBC count	Normal/Low	Normal/High	Normal/Low

Management Based on Diagnosis

For Iron Deficiency Anemia

1. Oral iron supplementation:

   • Ferrous sulfate 200 mg twice daily (provides 35-65 mg elemental iron daily) 1
   • Continue for 3 months after hemoglobin normalizes to replenish iron stores
   • Expected improvement: 1-2 g/dL increase in hemoglobin within 2-4 weeks

2. If oral iron fails or is not tolerated:

   • Consider parenteral iron preparations (iron sucrose, ferric carboxymaltose, iron dextran) 1

3. Identify and treat underlying cause:

   • Gastrointestinal bleeding is the most common cause in adults 2
   • Consider GI malignancy evaluation, especially in older adults
   • Assess for menstrual blood loss in women of reproductive age

For Thalassemia Trait

• Generally requires no specific treatment
• Genetic counseling may be appropriate
• Avoid unnecessary iron supplementation if iron studies are normal

For Anemia of Chronic Disease

• Treat underlying condition
• Consider erythropoietin therapy if anemia persists despite addressing primary condition 1

Monitoring and Follow-up

• Check hemoglobin weekly until stable, then monthly
• Monitor iron parameters (ferritin, transferrin saturation) regularly
• Continue follow-up at three-month intervals for one year after normalization 1

Common Pitfalls to Avoid

1. Overlooking functional iron deficiency - Patients may have functional iron deficiency despite normal/elevated ferritin, especially with chronic inflammation 1

2. Inadequate investigation - An MCV of 68 is very low and strongly suggests either severe iron deficiency or thalassemia trait; both require thorough evaluation 1, 2

3. Missing concomitant conditions - Iron deficiency can coexist with thalassemia or anemia of chronic disease 3

4. Premature cessation of iron therapy - Treatment should continue for 3 months after hemoglobin normalizes to fully replenish iron stores 1

5. Inappropriate iron supplementation - Avoid iron supplementation in patients with thalassemia trait and normal iron studies 4