What are the initial steps in evaluating a blood cancer workup?

Initial Steps in Blood Cancer Workup

The initial evaluation of a blood cancer workup should include a comprehensive laboratory assessment with complete blood count (CBC) with differential, peripheral blood smear examination, bone marrow aspiration and biopsy for morphologic and cytogenetic evaluation, and quantitative RT-PCR to establish the presence of quantifiable disease markers. 1

Core Initial Diagnostic Steps

Laboratory Testing

• Complete blood count (CBC) with differential - Essential first step to identify abnormalities in blood cell counts and morphology 1
• Chemistry profile - To assess organ function and detect metabolic abnormalities 1
• Peripheral blood smear review - For morphologic examination of blood cells 1
• Hepatitis B panel - Required before initiating certain therapies 1

Bone Marrow Evaluation

• Bone marrow aspirate and biopsy - Critical for:
  • Morphologic examination
  • Cytogenetic evaluation
  • Establishing disease baseline 1
  • Determining cellularity and fibrosis 2

Molecular and Cytogenetic Testing

• Quantitative RT-PCR - To establish presence of quantifiable disease-specific transcripts 1
• Bone marrow cytogenetics - To detect chromosomal abnormalities 1
• FISH (Fluorescence in situ hybridization) - If bone marrow evaluation is not feasible, can be performed on peripheral blood 1
• Flow cytometry - For immunophenotyping and establishing aberrant phenotypes for monitoring 1

Disease-Specific Workup

For Chronic Myeloid Leukemia (CML)

1. Confirm BCR-ABL1 presence - By quantitative RT-PCR or FISH 1
2. Bone marrow examination - To establish disease phase and detect myelofibrosis 2
3. Cytogenetic analysis - To detect additional chromosomal abnormalities 1

For Acute Leukemia

1. Multicolor flow cytometry - For lineage determination (B-ALL, T-ALL, AML, or mixed phenotype) 1
2. Cytogenetic analysis - For prognostic stratification 1
3. Molecular studies - Disease-specific genetic markers 1
4. Lumbar puncture - For CSF examination in suspected CNS involvement 1

Practical Considerations

When Bone Marrow Biopsy is Essential

• When peripheral blood analysis is inconclusive
• When disease phase determination is critical (particularly for CML) 2
• When myelofibrosis is suspected (occurs in 25% of CML cases and affects prognosis) 2
• When blast percentage needs accurate assessment 2

Common Pitfalls to Avoid

1. Relying solely on peripheral blood - May miss critical bone marrow findings in 25% of cases 2
2. Inadequate sample collection - Ensure proper technique for bone marrow aspiration and biopsy
3. Delayed processing - Samples should be processed promptly for optimal results
4. Failure to perform cytogenetics - Critical for diagnosis and prognosis
5. Not ordering appropriate molecular tests - Disease-specific markers are essential for diagnosis and monitoring

Special Situations

When Peripheral Blood Can Substitute for Bone Marrow

• When bone marrow aspiration is not feasible (dry tap)
• When patient condition prohibits bone marrow examination
• For initial screening before proceeding to more invasive testing 1

For Extramedullary Disease

• Tissue biopsy of affected sites when blood and bone marrow are not involved 1
• Fresh tissue collection for flow cytometry and molecular studies 1

By following this systematic approach to blood cancer workup, clinicians can ensure accurate diagnosis, proper disease classification, and appropriate treatment selection to improve patient outcomes.