Peripheral Blood Smear Interpretation Guidelines
Preparation and Examination
- At least 200 circulating nucleated cells per smear should be systematically analyzed by an experienced hematologist 1
- Samples should be collected under sterile conditions in sodium heparin tubes with optimal concentration of 20 IU/mL 2
- Specimens should be processed as soon as possible after collection, ideally within 24 hours 2
Systematic Examination Approach
- Assess Red Blood Cell (RBC) morphology for size variations (microcytosis, macrocytosis) 1
- Perform a differential count of at least 100 White Blood Cells (WBCs) and identify and quantify neutrophils, lymphocytes, and monocytes 2, 3
- Evaluate WBC morphology for nuclear changes (hypersegmentation, hyposegmentation) and cytoplasmic changes (toxic granulation, vacuolization) 2
Special Considerations for Plasma Cell Disorders
- Careful examination of peripheral blood smears is essential in suspected plasma cell disorders 3
- The presence of circulating plasma cells may indicate plasma cell leukemia (PCL) if ≥20% circulating plasma cells and/or absolute count >2×10^9/L plasma cells 3
- Lower thresholds (≥5% plasma cells or ≥0.5×10^9/L) should be noted as they may represent early PCL 3
Advanced Diagnostic Techniques
- Flow cytometry is recommended to confirm clonality of suspicious cells, evaluate specific cell markers, and distinguish between malignant and reactive processes 1, 2
- Cytogenetic analysis may be necessary for suspected hematologic malignancies 2