Understanding the Tests for CLL

The first signs of chronic lymphocytic leukemia (CLL) are often detected by blood work during a routine doctor’s visit. Some people may have physical symptoms, like weight loss, fatigue or swollen lymph nodes which usually indicates an advanced stage of the disease. Several blood tests will be done to confirm the diagnosis. Someone with CLL usually has a high white blood cell count and a low red cell count.

“In terms of the path that patients go on when they’re first diagnosed with CLL, it can vary quite a bit,” says Dr. Matthew Davids, an oncologist and director of clinical research in the Division of Lymphoma at Dana Farber Cancer Institute. “Many patients are actually asymptomatic at the time of diagnosis, and it’s just a routine blood count that leads to the discovery of the disease.  This is often just an elevated lymphocyte count that’s not associated with any symptoms.”

How Is a CLL Diagnosis Confirmed?

If your doctor suspects you may have CLL, the diganosis will be confirmed with a variety of tests.

These include:

• Blood tests
• Health history and exam
• Tests on the cancer cells

A flow cytometry test identifies the distinctive markers that distinguish CLL cells.

“A flow cytometry test looks at certain markers on the leukemia cells…that tell us what type of leukemia people have,” explains Dr. Nicole Lamanna, a hematologist/oncologist at Columbia University Herbert Irving Comprehensive Cancer Center.

According to the National Comprehensive Cancer Network CLL guidelines, a diagnosis of CLL is made based on three results from the flow cytometry test:

• The leukemia cells often have a specific pattern of proteins on their surface (immunophenotype) that includes CD5, CD19, and CD23, some CD20, and no CD10 proteins.
• The leukemia cells are copies of the same cell (monoclonality).
• There are at least 5,000 monoclonal B lymphocytes in blood (5 x 10%/L).

If a diagnosis cannot be determined using blood flow cytometry, a lymph node biopsy or bone marrow biopsy will be performed.  A lymph node biopsy tests a sample of lymph node tissue. Lymph nodes produce white blood cells and can become inflammed when they are trying to fight an infection or cancer cells. In a bone marrow biopsy, a sample of the bone marrow is removed from the hip bone to examine the leukemia cells in the bone marrow.

Testing to Determine Treatment for CLL

“One important thing to remember when a person has CLL is that you need some special genetic studies at the time of diagnosis to be able to modify or pick treatments that we use for patients,” explains Dr. Julie Vose, chief of hematology/oncology at the University of Nebraska Medical Center and Buffet Cancer Center.  These tests can also help with the prognosis.

Genetic tests on the cancer cells include:

FISH (flourescence in situ hybridization) testing: This test “finds the specific abnormalities in the CLL cells,” Dr. Vose says. This test can show missing parts of chromosomes or extra chromosomes.

Mutation test: Looks at how mature the cancer cells are and checks for mutations in TP53 and IGHV genes.

Karotyping: Helpful for determining defects in chromosomes.

Questions to Ask Your Doctor

• Which tests will you perform to confirm a CLL diagnosis?
• Which tests will you perform to determine the best ways to treat my CLL?
• How will these tests be conducted?
• Is there anything I need to do to prepare for the tests? Will they be uncomfortable?

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