Laboratory Tests for Diagnosing Blood Cell Dyscrasias
The diagnosis of blood cell dyscrasias requires a comprehensive panel of laboratory tests including complete blood count with differential, serum and urine protein studies, bone marrow examination, and specialized tests based on suspected diagnosis. 1
Initial Laboratory Evaluation
Blood Cell Assessment
- Complete Blood Count (CBC) with differential
- Hemoglobin and hematocrit (to assess anemia)
- Red blood cell count and indices (MCV, MCH, MCHC)
- White blood cell count with differential
- Platelet count
- Peripheral blood smear examination (to evaluate morphological abnormalities, rouleaux formation) 1
Biochemical Parameters
- Comprehensive metabolic panel
- Blood urea nitrogen (BUN)
- Serum creatinine and creatinine clearance
- Serum calcium
- Liver function tests (AST, ALT, bilirubin)
- Serum albumin
- Lactate dehydrogenase (LDH)
- Beta-2 microglobulin (important prognostic marker) 1
Protein Studies
Serum Protein Analysis
- Serum protein electrophoresis (SPEP) - identifies monoclonal protein bands
- Serum immunofixation electrophoresis (SIFE) - characterizes the type of monoclonal protein
- Serum free light chain (FLC) assay - quantifies kappa and lambda free light chains and their ratio 1
- Quantitative immunoglobulins (IgG, IgA, IgM) - measures levels of each immunoglobulin class 1
Urine Protein Analysis
- 24-hour urine collection for total protein
- Urine protein electrophoresis (UPEP)
- Urine immunofixation electrophoresis (UIFE) 1
Bone Marrow Studies
Bone Marrow Aspiration and Biopsy
- Morphological assessment
- Quantification of plasma cells or abnormal cells
- Assessment of dysplasia in cell lines
- Enumeration of blasts
- Evaluation for ring sideroblasts 1
- Bone marrow biopsy
- Assessment of cellularity
- Evaluation of fibrosis
- Topography of abnormal cells 1
Specialized Bone Marrow Studies
- Flow cytometry immunophenotyping
- Enumeration of abnormal cell populations
- Characterization of cell surface markers
- Assessment of clonality 1
- Cytogenetic analysis
- Karyotyping to identify chromosomal abnormalities
- Fluorescence in situ hybridization (FISH) for specific genetic abnormalities 1
- Molecular genetic studies
- Targeted gene sequencing
- Next-generation sequencing when indicated 1
Disease-Specific Testing
For Plasma Cell Disorders
- Serum viscosity - particularly for IgM paraproteins (Waldenström's macroglobulinemia) 2
- Serum erythropoietin level - for suspected myeloma 1
- Beta-2 microglobulin - important prognostic marker 1
For Myelodysplastic Syndromes
- Iron studies (serum iron, ferritin, total iron binding capacity)
- Vitamin B12 and folate levels
- Reticulocyte count
- Cytogenetic analysis - critical for diagnosis and prognosis 1
For Immunodeficiency Disorders
- Lymphocyte subset analysis
- Immunoglobulin levels
- Specific antibody titers
- In vitro lymphocyte proliferation studies 1
Imaging Studies
- Skeletal survey - for suspected multiple myeloma
- MRI, CT, or PET-CT - to evaluate for bone lesions or extramedullary disease 1
Common Pitfalls and Considerations
- Timing of sample collection - Protein studies should be performed before initiating therapy as treatment can affect results
- Sample handling - Proper collection and processing is critical, especially for bone marrow studies
- Interpretation challenges - Some findings may be nonspecific; correlation with clinical presentation is essential
- Follow-up testing - Serial measurements are often needed to monitor disease progression or treatment response
- Pre-analytical variables - Hydration status, medications, and recent procedures can affect results 1
When evaluating for blood cell dyscrasias, it's important to recognize that the specific testing algorithm should be guided by the suspected diagnosis, with initial screening tests followed by more specialized studies as indicated by clinical findings and initial test results.