What is the interpretation of a CBC showing normal hemoglobin, elevated RDW, and thrombocytopenia?

CBC Interpretation: Thrombocytopenia with Anisocytosis

This CBC shows thrombocytopenia with significant anisocytosis (elevated RDW), suggesting a potential bone marrow disorder affecting multiple cell lines despite normal hemoglobin levels. 1, 2

Key Findings in the CBC:

• Normal RBC count (4.1), hemoglobin (13.3), and hematocrit (39) 1
• Markedly elevated RDW at 57% (normal is typically ≤14.0%) 1, 2
• Thrombocytopenia with platelet count of 62 (significantly below normal range) 2
• Elevated MPV at 12.8, suggesting larger platelets 2

Clinical Interpretation:

Significance of Elevated RDW with Normal Hemoglobin:

• The extremely high RDW (57%) indicates severe anisocytosis (variation in red cell size) despite normal hemoglobin 1, 2
• This pattern suggests early or compensated hematologic disorder where the body is maintaining adequate hemoglobin despite underlying pathology 2
• The combination of normal MCV with markedly elevated RDW may indicate:
  • Early iron deficiency not yet affecting overall hemoglobin 1
  • Vitamin B12 or folate deficiency in early stages 2
  • Hemolysis with compensatory production 2

Significance of Thrombocytopenia with Elevated MPV:

• Low platelet count (62) with high MPV (12.8) suggests:
  • Increased platelet turnover or destruction 3
  • Possible bone marrow disorder affecting multiple cell lines 2

Differential Diagnosis:

• Myelodysplastic syndrome (affecting multiple cell lines with high RDW and thrombocytopenia) 2
• Early vitamin B12 or folate deficiency (can cause elevated RDW before anemia develops) 4
• Immune thrombocytopenia with concurrent early nutritional deficiency 2
• Bone marrow infiltration (e.g., malignancy, fibrosis) 3
• Early/compensated hemolytic process 2

Recommended Workup:

• Complete blood count with peripheral smear examination to assess red cell morphology and platelet appearance 1, 2
• Reticulocyte count to assess bone marrow response 1
• Iron studies: serum ferritin, transferrin saturation to rule out iron deficiency 1
• Vitamin B12 and folate levels 2
• Hemolysis panel: LDH, haptoglobin, bilirubin 2
• Inflammatory markers: CRP, ESR 1
• Consider bone marrow examination if diagnosis remains unclear, especially with bi-cytopenia (affecting both red cells and platelets) 2

Common Pitfalls to Avoid:

• Focusing only on the normal hemoglobin and missing the significance of the markedly elevated RDW 1, 2
• Attributing thrombocytopenia to a single cause without considering a potential common etiology affecting both cell lines 3
• Overlooking the possibility of early myelodysplastic syndrome or other bone marrow disorders when hemoglobin is still normal 2
• Failing to investigate for potential vitamin deficiencies that can cause elevated RDW before anemia develops 4