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Test Before Treat™ One-pager

In science and medicine, information is constantly changing and may become out-of-date as new data emerge. All articles and interviews are informational only, should never be considered medical advice, and should never be acted on without review with your health care team.

The PDF document below is a one page summary of what you need to know about the 3 most important tests that need to be done to guide your CLL treatment.

Please feel free to read it, download it, and/or print it out to share with your health care provider, if need be, or with other patients who may benefit from this information.

Test Before Treat™

Once we know that our CLL needs treatment, we need to know how to treat it.

Current NCCN and iwCLL guidelines tell us that it is critical to get appropriate predictive testing before the first and every subsequent therapy. Results of these tests give us information about the biology of our disease, which in turn, gives us the ability to make a reasonable prediction as to which therapies offer us the best chance of success.

Simply put, depending on what the tests show, some commonly prescribed CLL therapies likely will work for us and others may not! 

While there are many tests that might help CLL patients needing treatment to make their most informed decision, these three tests are essential:

  1. FISH (Interphase fluorescence in situ hybridization) test looks for common chromosomal abnormalities that predict the likelihood that various CLL treatments will be effective and durable. For example, if FISH testing finds there is a deletion of the short arm of the 17 chromosome or del(17p) we know that traditional chemo-immunotherapy (CIT) such as fludarabine, cyclophosphamide and rituximab (FCR) or the combination of bendamustine and rituximab known as BR, will not be effective and should be avoided.
  2. Additionally, it is important to test IgVH (also called IgHV, both are correct) mutation status. IgVH mutation status almost never changes over time, so it is generally not recommended that it be retested. It is important because we know that patients with a “mutated” IgVH immunoglobulin do much better with FCR based therapies than those who are unmutated. Generally only patients who have mutated IgVH should consider FCR based therapies.
  3. The 3rd and newest predictive factor is genetic testing for mutation of the TP53 TP53 is the gene on the short arm of the 17th chromosome that helps chemo to work and suppress cancer growth. It has been called the “guardian of the genome” because it tries to repair damaged genetic material in the CLL cells and if can’t repair what’s broken by chemo or any other cause, it signals the cell to commit programmed cell death or apoptosis. You can see how handy TP53 would be in suppressing cancer or helping chemo to work. However, if it’s missing as in del(17p) or mutated, and therefore dysfunctional, as discovered by genetic testing, generally chemotherapy will not work and the CLL can be harder to manage.

If you know the status of these 3 tests before your 1st and every subsequent treatment you can best map out your treatment strategy. FISH and TP53 need to be checked and rechecked before the first and any subsequent treatments as they can change over time, usually for the worse. IgVH mutation status is considered stable over time.

Test Before Treat™

  • Test FISH and TP53 Mutation before every treatment
  • Test IgVH mutation status before the 1st treatment
  • Deletion 17p or del(17p) = NO CHEMOTHERAPY
  • TP53 mutation = NO CHEMOTHERAPY
  • IgVH unmutated = NO FCR
  • IgVH mutated = possible FCR


As new and better treatments are developed to treat Chronic Lymphocytic Leukemia, and Small Lymphocytic Lymphoma (CLL / SLL), testing for subtypes of the disease is becoming more important for prognosis and selection of the best treatment options.
Patient, Know Thyself Mark Hoffman is a long-time CLL patient advocate and facilitator of the CLL Society Patient & Caregiver Support Group in San Diego, CA. In this article from Cancer Health, Mark echoes the importance of the Test Before Treat™ campaign by sharing his story. When Mark was
At the American Society of Hematology’s (ASH) 2020 conference, there was research on looking at the genome of CLL and how different genetic markers might have predictive and value. Dr. Brian Koffman, Chief Medical Officer and Executive Vice President of CLL Society, interviewed Dr. Adrian Wiestner, a senior investigator at
CLL Society On Demand Ed Forum: ASH 2020 Comes to You – Session 1: Encouraging Updates on Drugs in Development + the Sad State of Test Before Treat Recorded Thursday, February 4, 2021 Continue to Session 2: CLL Treatments: Chemotherapy, Immunotherapy, and Targeted Agents CLL Society Resources Download