Understanding Test Results
Genetic testing results are unique to each patient and can be complex. Below are some frequently asked questions about genetic testing and genetic testing results.
What types of genetic testing does Mayo Clinic offer?
The Center for Individualized Medicine facilitates multiple types of genetic testing for Mayo Clinic patients.
If you're generally in good health, you can request predictive, or proactive, genetic testing. This type of testing often includes screening for genes linked to conditions such as hereditary cancer or cardiovascular disease. Knowing that you have any of these genes can help your physician recommend things you can do that might reduce your risk. Your physician can also monitor you more closely to catch and treat disease earlier, increasing chances of a good outcome.
You can also get genetic testing if you have a personal history of a specific condition. Examples include recurrent fevers, possible maturity-onset diabetes of the young (MODY) or pulmonary fibrosis that doesn't have a known cause, among others.
The Center for Individualized Medicine also offers genetic testing to diagnose rare diseases. An example of this is if your doctors suspect that you or your child has a rare genetic disease, but previous tests haven't provided answers about what the disease could be. This may include early-onset disease or a disease in which you have symptoms that can't be explained. In these cases, genetic testing, such as whole-exome or genome sequencing, may be effective to find the underlying genetic cause.
Pharmacogenomic testing, or drug-gene testing, assesses how your genes affect your response to specific drugs. This type of testing may provide information on prescription medication choices, dosing recommendations or both based on your unique genetic makeup.
Finally, if you have advanced cancer, you may choose to undergo genetic testing to help you and your care team make decisions about your treatment. This often includes genomic sequencing of the tumor to look for alterations, which may identify new or different treatment options.
What are common results from genetic testing?
There are three possible results you can receive from genetic testing: positive, negative or uncertain. The meaning of these results depends on multiple factors, such as the type of genetic testing that was performed and your personal and family history, among others.
A positive result means that testing has identified a gene change or genetic mutation in one or more of the genes analyzed. This type of result may be called a pathogenic or disease-causing variant. A positive result typically means that you're at higher risk of developing a hereditary condition.
Sometimes, a positive result can explain why you're having certain symptoms. Or, it can alert you to a risk you didn't know about. It could lead to changing how you and your doctor manage your health care. Your biological family members may wish to consider genetic counseling and testing to better assess their own risk of also having the variant, as these changes often run in families.
Genetic testing results may also be negative. A negative result means that no gene changes were identified in the genes analyzed. While a negative result — meaning no genetic condition or risk was identified — is often reassuring, it typically cannot rule out a genetic condition, as there may be undiscovered genes or variants that were not included on the test.
Genetic testing and the knowledge of genetics are constantly improving. Therefore, if you received negative results, you may wish to ask your care team about updated genetic testing in the future.
Sometimes, genetic testing results can be uncertain. This means that one or more variants were found; however, it's unclear whether those variants could be contributing to a disease or disease risk, or if they're just a normal part of human genetic variation. Uncertain results are relatively common, especially when a large number of genes are analyzed.
Most of the time, an uncertain result wouldn't lead to changes in your medical care. Your care team might recommend additional testing for you, your family members or both to help clarify uncertain results. Over time, uncertain results may be changed to positive or negative once more information is known.
What should patients expect during and after receiving their genetic testing results?
You'll receive your genetic testing results from a specially trained doctor (medical geneticist), genomics nurse or genetic counselor. Genetic testing results could be communicated in a variety of ways, such as an in-person appointment, video visit or telephone call.
After receiving your results, it's common to meet with a genetic counselor to review the results and discuss next steps. The genetic counselor will often talk about topics including:
- What the result is
- What the result means for you
- How your medical care may change moving forward
- Implications for your family members
If results are positive, you will likely be referred to see specialized doctors who have experience with the diagnosed condition and its symptoms.
It's important to remember that each genetic testing result is unique. No matter what the results are, you should talk with your genetic health care specialists about the results and any questions or concerns you have.
How should patients prepare for an appointment with a genetic counselor?
You may get more out of your genetic counseling appointment if you gather certain information ahead of time. This may include gathering medical information and records on yourself and your family members and obtaining a list of family members, including current ages or ages of death and cause of death.
Although having this information is helpful to the genetic counselor, it's not necessary. You should still meet with a genetic counselor even if you don't know a lot about your family history.
You may also wish to think about and write down questions or concerns ahead of time so that you can ask the genetic counselor during the appointment.
You may want to consider bringing someone with you to the genetic counseling appointment, such as a friend or family member. That person can both support you and help listen, take notes to recall the information, and ask questions.
Learn more about genetic counselors and other members of your care team.
How are patients protected from genetic discrimination?
The Genetic Information Nondiscrimination Act of 2008 (GINA) is a federal law that protects individuals from the misuse of genetic information (genetic discrimination) in health insurance and employment.
GINA makes it illegal for health insurers to use genetic testing results or family histories as a reason to deny health insurance or decide how much it costs. GINA also makes it illegal for employers to use genetic testing results or family histories when making decisions about employment.
GINA does not cover other insurance types, such as life insurance, long-term care insurance and supplemental disability insurance. There are a few additional exceptions to GINA that can be found on the GINA website.
Genetic counselors are good sources of information about GINA and can answer many questions about genetic discrimination.
Where can patients find additional information?