What is the interpretation of this Complete Blood Count (CBC) showing microcytic hypochromic anemia?

Interpretation of CBC: Microcytic Hypochromic Anemia

This CBC shows a classic pattern of iron deficiency anemia with low hemoglobin (9.3 g/dL), low RBC count (3.58 x10^6/μL), low hematocrit (30.3%), normal MCV (85 fL), and low MCH (26.0 pg) and MCHC (30.7 g/dL) values.

CBC Analysis

The key abnormalities in this CBC are:

• Hemoglobin: 9.3 g/dL (Low; reference range: 13.0-17.7 g/dL)
• RBC count: 3.58 x10^6/μL (Low; reference range: 4.14-5.80 x10^6/μL)
• Hematocrit: 30.3% (Low; reference range: 37.5-51.0%)
• MCV: 85 fL (Normal; reference range: 79-97 fL)
• MCH: 26.0 pg (Low; reference range: 26.6-33.0 pg)
• MCHC: 30.7 g/dL (Low; reference range: 31.5-35.7 g/dL)

Differential Diagnosis

1. Iron Deficiency Anemia (IDA)

   • Most common cause of microcytic hypochromic anemia 1
   • Typically presents with low MCV, MCH, and MCHC
   • Note: This patient has a normal MCV but low MCH and MCHC, which can occur in early iron deficiency

2. Thalassemia

   • Inherited disorder of hemoglobin synthesis
   • Usually presents with more profound microcytosis relative to the degree of anemia
   • Often has normal or elevated RBC count

3. Anemia of Chronic Disease

   • Can present with microcytic hypochromic pattern
   • Usually less severe microcytosis than iron deficiency

4. Sideroblastic Anemia

   • Genetic disorder affecting heme synthesis
   • Can present with microcytic hypochromic pattern 2
   • Often has increased iron stores despite microcytosis

5. Atransferrinemia/Hypotransferrinemia

   • Rare genetic disorder with deficiency of transferrin
   • Presents with severe hypochromic microcytic anemia 3

Diagnostic Approach

To confirm the diagnosis, the following tests should be ordered:

• Serum iron
• Total iron-binding capacity (TIBC)
• Transferrin saturation
• Serum ferritin
• Reticulocyte count

If these tests are inconclusive:

• Hemoglobin electrophoresis (to rule out thalassemia)
• Bone marrow examination (gold standard for diagnosing iron deficiency) 1
• Serum transferrin receptor levels (elevated in iron deficiency)

Management

For confirmed iron deficiency anemia:

1. Oral Iron Supplementation 4

   • First-line treatment: Ferrous sulfate 324 mg (65 mg elemental iron) 2-3 times daily
   • Continue therapy for 2-3 months after hemoglobin normalizes to replenish iron stores
   • Monitor response with repeat CBC after 2-4 weeks of therapy

2. Alternative Iron Formulations

   • If intolerant to ferrous sulfate: ferrous gluconate or ferrous fumarate
   • Extended-release preparations may have fewer GI side effects but lower absorption

3. Parenteral Iron

   • Consider if:
     • Oral iron is not tolerated
     • Malabsorption is present
     • Losses exceed oral replacement capacity
   • Options include iron dextran, iron sucrose, ferric gluconate, or ferric carboxymaltose

4. Blood Transfusion 4

   • Reserved for severe symptomatic anemia
   • Consider if hemoglobin <7 g/dL or patient has cardiac symptoms
   • One unit of packed RBCs typically increases hemoglobin by approximately 1 g/dL

Important Considerations

• Identify and treat underlying cause: GI bleeding, menorrhagia, pregnancy, malabsorption
• Monitor response: Expect hemoglobin to increase by 1-2 g/dL every 2-3 weeks with appropriate therapy
• Avoid inappropriate iron supplementation in conditions like thalassemia trait or sideroblastic anemia, where iron overload is a risk 4
• Consider rare genetic causes if standard treatments fail 2

Pitfalls to Avoid

• Failing to investigate the underlying cause of iron deficiency
• Stopping iron supplementation too early (before replenishing iron stores)
• Overlooking the possibility of mixed deficiency states (e.g., iron and B12/folate)
• Neglecting family screening in hereditary conditions like thalassemia or sideroblastic anemia 4

In summary, this CBC most likely represents iron deficiency anemia, but further testing is needed to confirm the diagnosis and determine the underlying cause.