What RBC morphology is expected with a low MCV and low hemoglobin level?

RBC Morphology Analysis Based on Laboratory Values

The RBC morphology consistent with the given laboratory values (MCV = 90 fL, Hgb = 9.2 g/dL, RBC = 3.5 x 10^6/μL) is normocytic, hypochromic (option B).

Analysis of Laboratory Values

The interpretation of RBC morphology requires careful analysis of the complete blood count parameters:

1. MCV (Mean Corpuscular Volume):

   • MCV = 90 fL falls within the normocytic range (80-100 fL) 1
   • This indicates normal red blood cell size

2. Hemoglobin (Hgb):

   • Hgb = 9.2 g/dL is below normal range, indicating anemia
   • This suggests decreased hemoglobin content within the cells

3. RBC Count:

   • RBC = 3.5 x 10^6/μL is below the normal range
   • This confirms the presence of anemia with reduced red cell mass

Morphological Classification

The combination of these values allows us to determine the RBC morphology:

• Cell Size (MCV): Normocytic (normal size) as MCV is within normal range (80-100 fL)
• Hemoglobin Content: Hypochromic (reduced hemoglobin content) as evidenced by low hemoglobin with normal cell size
• MCHC (Mean Corpuscular Hemoglobin Concentration): While not provided directly, it can be calculated and would be reduced, confirming hypochromia

Ruling Out Other Options

• Option A (Poikilocytosis and anisocytosis): These refer to variation in shape and size of RBCs, not specifically indicated by the normal MCV value
• Option C (Macrocytic, Normocytic): Contradictory terminology; cells cannot be both macrocytic (MCV >100 fL) and normocytic (MCV 80-100 fL) 1
• Option D (Microcytic with spherocytes): Incorrect as MCV is normal, not low (<80 fL), and there's no indication of spherocytes 2

Clinical Significance

This normocytic, hypochromic pattern can be seen in:

1. Early iron deficiency anemia (before microcytosis develops)
2. Anemia of chronic disease
3. Mixed deficiency states
4. Early stages of hemoglobinopathies

The reduced RBC count with normal MCV but low hemoglobin suggests a condition where hemoglobin synthesis is impaired while cell size remains normal 1, 2.

Diagnostic Considerations

When encountering normocytic, hypochromic RBCs, further testing should include:

• Iron studies (ferritin, transferrin saturation)
• Reticulocyte count to assess bone marrow response
• Evaluation for chronic inflammatory conditions
• Consideration of mixed nutritional deficiencies

This pattern differs from classic iron deficiency anemia, which typically presents with microcytic (MCV <80 fL), hypochromic cells 2, 3.