How Does Genetic Testing Work?

Development of this resource was generously supported by Myriad Genetics. 

Decide if Genetic Testing is Right for You and Your Family


Before you have a genetic test, you should have the opportunity to understand the testing procedure, the benefits and limitations, and the possible consequences of the results. The process of learning about the test and giving your permission is called informed consent.


Genetic testing is often done as part of a genetic consultation. If you decide to proceed with genetic testing, the following people can order a genetic test:


  • Medical geneticists,

  • Primary care doctors,

  • Gastroenterologists (GI), or

  • Nurse practitioners.


Genetic testing is a personal choice. There are benefits, risks, and limitations of testing. The decision can be simple or complicated. Be sure to discuss medical, familial, social and emotional aspects of testing with your medical provider.


How does the test work?


The genetic material (DNA) needed for a genetic test is most easily obtained from blood or from buccal (inside-the-cheek) cells. Thus, your genetic test will include a blood draw, mouth rinse or inner cheek swab. The blood or mouth is the sent to a laboratory that specializes in genetic testing. Scientists analyze the gene or genes associated with the hereditary colon cancer syndrome you are suspected of having. Depending on the laboratory and the genes being analyzed, this process can take 2-12 weeks. The genetic test results are sent in writing to your doctor or genetic counselor, who will contact you to discuss these results. Similar to how a builder uses a set of blueprints to know how to construct a home, your body uses a set of genetic blueprints called DNA to grow, function, and heal. DNA carries the information that guides our bodies to replenish and repair itself as needed. Genetic tests identify changes in our genetic blueprints. These changes are called mutations.


Genetic testing can be used to confirm or pinpoint a diagnosis of a hereditary colon cancer syndrome like Familial Adenomatous Polyposis, MUYTH-Associated Polyposis, Lynch Syndrome, etc. A precise genetic diagnosis helps clarify your risk of developing a cancer. In turn, this can help you and your doctors decide what type of cancer screening you need and how often. In some cases, cancers can be prevented. If there is a precise genetic diagnosis, family members can be tested to see whether or not they inherited the condition.


There are many different types of genetic tests, so it is in your best interest to work with a specialist, such as a genetic counselor, who can identify the best strategy for genetic testing for you.




1) What are the benefits and risks of genetic testing?


2) What is the cost of genetic testing?


3) What have others experienced with genetic testing?



* Information used to develop this page was sourced from the Genetics Home Reference and reviewed by the Hereditary Colon Cancer Foundation's Patient Education Team.