A complete blood count (CBC) test reviews the number of white blood cells, red blood cells, and platelets in the patient's blood. CLL affects B-cells, a type of lymphocyte white blood cell. The CLL cells don't die when they should and crowd out other types of blood cells (the crowding out process typically happens slowly for CLL patients).

A CLL patient should receive a CBC with differential test. A differential means the doctor also looks at the balance between the different white blood cells (basophils, neutrophils, eosinophils, monocytes, and lymphocytes). 

The CBC with differential test is completed by the doctor taking a sample of the patient's blood and looking at it under a microscope. The CLL patient's lab results will typically show a high number of B-cell lymphocytes. Other blood cell types like red blood cells or platelets may be low. The blood cell environment factors into when treatment is needed. See here for blood count qualifications to start treatment.

See here other CLL tests patients need their doctor to complete here. Need help finding a CLL specialist? Check out HealthTree's CLL Specialist Directory.