Chronic lymphocytic leukemia (CLL) is most commonly discovered when an elevated white blood cell (lymphocyte) count is noted in a routine blood test. A Mayo Clinic doctor specializing in blood disorders (hematologist) confirms the diagnosis through one or more of the following ways:
- Medical history review and physical exam
- Complete blood count. This test measures the number of white blood cells, red blood cells and platelets in a blood sample. A higher number of a certain type of white blood cells (B cells) may indicate that you have CLL.
- Flow cytometry. Blood cells are examined with immune system proteins (antibodies) to determine if they are cancerous (malignant). If leukemia cells are present, this test can help predict how aggressively they've spread.
- Bone marrow biopsy. A bone marrow sample is removed for examination by a pathologist (specialist in examining body tissue) to determine whether the cancer has spread to those cells. Mayo Clinic's pathologists are highly skilled at rapidly identifying CLL stage and severity, which enables the treatment team to determine the most appropriate treatment or combination of treatments for you.
- Lymph node biopsy. A biopsy of the lymph nodes assesses whether cancer cells have spread to the lymphatic system.
To predict the likely course (prognosis) of leukemia, your doctor may also recommend the following, more specialized tests. These tests provide your treatment team with key information regarding the need and urgency of treatment versus observation. They may also predict response to treatment and likelihood of relapse.
- FISH (fluorescence in situ hybridization). This test determines the presence of abnormalities in specific chromosomes of CLL cells, which are associated with more or less aggressive forms of cancer.
- Immunoglobulin gene mutation status (IGVH). IGVH testing helps predict a more aggressive (if the gene is not mutated) or more favorable (if the gene is mutated) course of CLL. This technically complex test is only available at some medical centers with research laboratories.
- Beta-2-microglobulin, ZAP 70 and CD38. Analysis of this panel of tests can help predict the timeline of cancer progression from diagnosis to potential treatment.
Read more about diagnosis of CLL, complete blood count and bone marrow biopsy at Mayoclinic.com.