laboratory features

Last reviewed 01/2018

• peripheral blood:
  • WBC
• WBC usually greater than 15000 x 10^9 per litre, may be markedly elevated
• 75-98% of circulating cells may be lymphocytes
• lymphocyte count is more than 5 x 10^9/l (1)
• in blood smear, majority of lymphocytes are small, mature appearing with scanty cytoplasm, clumped chromatin, indistinct or absent nucleoli (1,2)
• red blood cells - distinguish anaemia secondary to bone failure from that due to autoimmune haemolytic anaemia
• platelets - usually normal; may be low secondary to bone marrow failure or to autoimmune thrombocytopenia

• peripheral blood flow cytometry
  • most valuable test for the confirmation of CLL
• immunophenotyping should be carried out in all patients who require treatment and is especially important in the following situations
• in patients with low lymphocyte counts (to confirm the diagnosis of CLL and to exclude reactive lymphocytosis)
• in patients with atypical lymphocyte morphology (to exclude other B- or T-cell lymphoproliferative disorders) (2)  
• classical immunophenotype of CLL are  weak monotypic surface immunoglobulin, CD5, CD19, and CD23 and weak or absent CD79B, CD22 and FMC7 (2)

Additional investigations which could be done include:

• bone marrow aspiration / biopsy - infiltration by lymphocytes
  • bone marrow examination is not carried out routinely except in cases where it is necessary
• when there is diagnostic difficulty
• as a prognostic indicator
• to document the response to therapy
• to assess haemopoietic reserve
• as a research investigation (1)

• Coomb's test (direct antiglobulin test ,DAT)
•  positive in 5% of patients
• should be done in all anaemic patients and before commencing therapy (2)

• serum Ig's - hypogammaglobulinaemia seen in two-thirds of cases dependent on duration of disease; monoclonal gammopathy - often IgM - seen in some cases

• uric acid - often normal; may become elevated with treatment

• imaging - chest X-ray, ultrasound of the abdomen (3)

Reference:

• (1) British Committee for Standards in Haematology 2010. Best practice in lymphoma diagnosis and reporting - Specific Disease Appendix  
• (2) Oscier D et al. Guidelines on the diagnosis and management of chronic lymphocytic leukaemia. Br J Haematol. 2004;125(3):294-317
• (3) Eichhorst B et al. Chronic lymphocytic leukaemia: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2010;21 Suppl 5:v162-4