What blood tests are recommended for a suspected lymphoma diagnosis?

Blood Tests for Suspected Lymphoma Diagnosis

For suspected lymphoma, a comprehensive blood workup should include complete blood count with differential, comprehensive metabolic panel, lactate dehydrogenase (LDH), beta-2 microglobulin, and hepatitis B and C testing as essential initial laboratory tests. 1

Essential Blood Tests

Initial Laboratory Evaluation

• Complete blood count (CBC) with differential 2, 1

  • Evaluates for cytopenias affecting multiple cell lines
  • Provides baseline hematologic parameters
  • Identifies presence of abnormal cells

• Comprehensive metabolic panel 2, 1

  • Includes liver and kidney function tests
  • Evaluates electrolyte balance

• Lactate dehydrogenase (LDH) 2, 1

  • Critical prognostic marker in most lymphoma subtypes
  • Elevated in aggressive disease and high tumor burden
  • Used in prognostic scoring systems (FLIPI, IPI)

• Beta-2 microglobulin 2, 1, 3

  • Independent prognostic factor for lymphoma outcomes
  • Correlates with tumor burden
  • Provides powerful risk stratification when combined with LDH

• Hepatitis B and C testing 2, 1

  • Essential before initiating rituximab or other CD20 monoclonal antibody therapy
  • Prevents reactivation of hepatitis during immunotherapy

• HIV screening 2, 1

  • Important due to association between HIV and certain lymphoma types

Additional Useful Tests

• Uric acid level 2

  • Evaluates risk for tumor lysis syndrome, especially in high-grade lymphomas

• Quantitative immunoglobulins (IgG, IgA, IgM) 2, 1

  • Particularly relevant in suspected B-cell lymphomas
  • May reveal immunoglobulin abnormalities characteristic of certain lymphoma types

• Protein electrophoresis 2

  • Identifies monoclonal proteins
  • Useful in distinguishing lymphoma from plasma cell disorders

Lymphoma-Specific Blood Tests

For Follicular Lymphoma

• FLIPI parameters 2
  • Hemoglobin level (<12 g/dL is adverse factor)
  • LDH (elevated is adverse factor)
  • Additional parameters include age, stage, and number of nodal sites

For Diffuse Large B-Cell Lymphoma

• IPI parameters 2
  • LDH (elevated is adverse factor)
  • Additional parameters include age, stage, performance status, and extranodal sites

Important Considerations

• Blood tests alone are insufficient for definitive diagnosis of lymphoma 2

  • Surgical specimen/excisional lymph node biopsy is required for definitive diagnosis
  • Core biopsies should only be performed when lymph nodes are not easily accessible
  • Fine-needle aspiration is generally inappropriate for initial lymphoma diagnosis

• Timing of blood tests is important:

  • Baseline tests should be performed before any treatment
  • Some parameters (like LDH) may be used for monitoring treatment response

• Interpretation of results should consider:

  • Age-specific reference ranges for all parameters 1
  • Potential impact of comorbidities on test results
  • Need for repeat testing in some cases

Common Pitfalls to Avoid

1. Relying solely on blood tests for diagnosis

   • Excisional biopsy remains the gold standard for lymphoma diagnosis
   • Blood tests provide supportive evidence and help with staging/prognosis

2. Missing hepatitis testing before rituximab therapy

   • Can lead to potentially fatal hepatitis reactivation

3. Overlooking the prognostic value of LDH and beta-2 microglobulin

   • These markers provide critical information for risk stratification 4, 3, 5

4. Failing to repeat abnormal tests

   • Confirmation of abnormal results is often necessary
   • Trending values over time provides valuable clinical information

Blood tests represent only one component of lymphoma evaluation, which should also include appropriate imaging studies and, most importantly, tissue biopsy for definitive diagnosis and classification.