Blood tests

Tests and procedures used to diagnose chronic lymphocytic leukemia include blood tests designed to:

• Count the number of cells in a blood sample. A complete blood count may be used to count the number of lymphocytes in a blood sample. A high number of B cells, one type of lymphocyte, may indicate chronic lymphocytic leukemia.

• Determine the type of lymphocytes involved. A test called flow cytometry or immunophenotyping helps determine whether an increased number of lymphocytes is due to chronic lymphocytic leukemia, a different blood disorder or your body's reaction to another process, such as infection.

  If chronic lymphocytic leukemia is present, flow cytometry may also help analyze the leukemia cells for characteristics that help predict how aggressive the cells are.

• Analyze lymphocytes for genetic abnormalities. A test called fluorescence in situ hybridization (FISH) examines the chromosomes inside the abnormal lymphocytes to look for abnormalities. Doctors sometimes use this information to determine your prognosis and help choose a treatment.

Other tests

In some cases, your doctor may order additional tests and procedures to aid in diagnosis, such as:

• Tests of your leukemia cells that look for characteristics that could affect your prognosis
• Bone marrow biopsy and aspiration
• Imaging tests, such as computerized tomography (CT) and positron emission tomography (PET)

Staging

Once a diagnosis is confirmed, your doctor determines the extent (stage) of your chronic lymphocytic leukemia. Your doctor will use information about your cancer to assign a stage — early, intermediate or advanced — that indicates the progression of your chronic lymphocytic leukemia.

In general, people with early-stage disease don't require immediate treatment. Those with intermediate-stage disease and advanced-stage disease may be given the option to begin treatment right away.