What is the interpretation and management of a CBC showing hypochromia and anisocytosis, along with thrombocytosis?

Interpretation and Management of CBC Showing Hypochromia, Anisocytosis, and Thrombocytosis

The CBC findings of low MCHC (30.4 g/dL), elevated RDW (16.2%), and high platelet count (453 x10³/uL) strongly indicate iron deficiency anemia with reactive thrombocytosis, requiring iron supplementation therapy. 1

Understanding the CBC Abnormalities

• MCHC of 30.4 g/dL (below normal range of 31.5-35.7 g/dL) represents hypochromia, indicating reduced hemoglobin concentration within red blood cells - a classic feature of iron deficiency anemia 1
• RDW of 16.2% (above normal range of 11.7-15.4%) indicates significant anisocytosis (variation in red cell size), which is a sensitive indicator of iron deficiency 1
• Platelet count of 453 x10³/uL (slightly above normal range of 150-450 x10³/uL) represents mild thrombocytosis, commonly associated with iron deficiency anemia 1

Diagnostic Approach

• Complete iron studies should be performed immediately, including:
  • Serum ferritin (most specific test for iron deficiency) 2
  • Transferrin saturation (TSAT) 2
  • Total iron-binding capacity (TIBC) 1
• A serum ferritin <30 μg/L and/or TSAT <20% confirms iron deficiency anemia 1
• Consider additional testing to rule out other causes of microcytic hypochromic anemia:
  • Hemoglobin electrophoresis if thalassemia is suspected (especially if RDW is normal or near normal) 2
  • B12 and folate levels to identify potential concurrent deficiencies 1
  • Inflammatory markers (CRP, ESR) to assess for anemia of chronic disease 1

Treatment Algorithm

1. First-line treatment: Oral iron supplementation 1, 2

   • Ferrous sulfate 200 mg three times daily (provides 60 mg elemental iron per tablet) 2
   • Alternative formulations (ferrous gluconate or ferrous fumarate) if ferrous sulfate is not tolerated 2
   • Add ascorbic acid (vitamin C) to enhance iron absorption 2

2. Monitor response to therapy: 1, 2

   • Expect hemoglobin rise ≥10 g/L within 2 weeks (confirms iron deficiency) 1
   • Continue iron therapy for 3 months after hemoglobin normalization to replenish iron stores 1
   • Monitor CBC parameters at regular intervals (every 4-6 weeks initially) 2

3. For non-responders or those with intolerance to oral iron: 2

   • Consider intravenous iron formulations 2
   • Investigate for potential causes of non-response:
     • Ongoing blood loss 2
     • Malabsorption 2
     • Non-compliance 1
     • Incorrect diagnosis 1

Differential Diagnosis

• Iron deficiency anemia (most likely based on CBC findings) 1, 3
• Thalassemia trait (typically shows more pronounced microcytosis with normal or elevated RBC count and minimal anisocytosis) 1
• Anemia of chronic disease (typically has normal or low TSAT with normal or elevated ferritin) 1
• Sideroblastic anemia (can present with hypochromia and variable RDW) 1

Important Considerations and Pitfalls

• Don't rely solely on hemoglobin levels for diagnosis - MCHC and RDW changes often precede significant drops in hemoglobin 3
• Don't miss underlying causes of iron deficiency - investigate for potential sources of blood loss (especially gastrointestinal) or malabsorption 2
• Don't overlook concurrent B12 or folate deficiency, which can mask the microcytosis of iron deficiency by causing macrocytosis 1
• Don't assume all microcytic, hypochromic anemias are iron deficiency - consider thalassemia traits, especially in appropriate ethnic populations 1
• Don't rely solely on ferritin in the setting of inflammation - use multiple parameters including TSAT and response to iron therapy 1