Diagnosis

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 changes. A test called fluorescence in situ hybridization (FISH) examines the chromosomes inside the cancerous lymphocytes to look for changes. 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 uses the information about your cancer to determine the stage of your chronic lymphocytic leukemia. The stage tells your doctor how aggressive your cancer is and how likely it is to get worse quickly.

Chronic lymphocytic leukemia stages can use letters or numbers. In general, the earliest stages of disease don't need to be treated right away. People with cancer in the later stages may consider beginning treatment immediately.