Genetic testing: Insight from Mayo Clinic specialists

Genetic testing is a powerful tool. Mayo Clinic specialists help you understand what to expect.

Lama Eldahdah, C.G.C.

Perhaps you have a family history of a genetic condition and you're considering genetic testing to determine your risk. Or maybe you've had worrisome results from a prenatal screening test and you're considering more comprehensive genetic testing. Whatever the circumstances, genetic testing is a powerful tool. After all, the results can have a profound effect on your life.

Here are answers to common questions about genetic testing from Lama Eldahdah, Melanie Lega and Marie Schuetzle, certified genetic counselors at Mayo Clinic, Rochester, Minn.

How should I prepare for genetic testing?

Melanie Lega, C.G.C.

Start by gathering as much information as you can about your family's medical history. Details about close relatives — both living and deceased — are especially important. Then collect your medical records, including any records from specialists or results from previous genetic testing. If you've been given access to medical records from any family members affected by genetic conditions, collect those records, too.

Next, write down any questions you have about genetic testing or specific genetic conditions. You might recruit a loved one or friend to help you ask questions or take notes.

It's also important to consider the emotional aspects of genetic testing. Genetic testing doesn't offer guarantees. Negative results don't erase all risks of disease, nor do positive results necessarily mean you will develop a disease. Sometimes test results are unclear or ambiguous, and sometimes answers aren't possible.

What happens during a genetic consultation?

Marie Schuetzle, C.G.C.

Before you have genetic testing, you'll need a genetic consultation. Most initial consultations last up to two hours. You'll start by documenting your personal and family medical history. In some cases, a genetic consultation includes a physical exam by a medical geneticist, a physician who specializes in the diagnosis and treatment of genetic conditions.

You'll also meet with a genetic counselor, a health professional who has a specialized graduate degree and experience in medical genetics and counseling. Your genetic counselor will make sure your medical history is complete, help you understand what genetic testing may — or may not — tell you, and answer any questions you may have. You'll also discuss specific genetic testing procedures, including any safety concerns for a particular genetic test, how long it takes to receive the test results and what the results might mean for you. Your genetic counselor may offer suggestions to help you build a support network, talk to family members about genetic testing or address any special concerns.

Can the genetic counselor tell me what to do?

The decision to pursue genetic testing is personal. No one can tell you what to do, and there's no obligation to pursue testing. Instead, your genetic counselor will facilitate your decision-making process.

Think about how you really feel about genetic testing. Have your questions been answered? Do you have all the information you need to make a good decision? Why do you want the test results? How will you feel if the results aren't definitive? What's holding you back or making the decision difficult?

Your genetic counselor can correct any misconceptions you may have about genetic testing, help you set clear goals and support you in making an informed decision.

What happens during the genetic test?

Often, genetic testing simply requires a blood sample. In other cases, a swab sample from the inside of your cheek may be needed. Prenatal genetic tests may require a sample of the placenta or amniotic fluid. Rarely, a skin or muscle biopsy might be necessary. The blood or tissue sample is then sent to a lab for analysis.

How long will it take to get the results?

That depends on the type of genetic testing. Results from a blood test might be available within a few weeks. Results from other types of genetic tests might take several months. Sometimes additional tests are needed to clarify the results.

What can I do while I'm waiting for the results?

Waiting for test results is tough. If you're concerned about how long it'll take to receive your results, clarify the expected wait upfront. You might make a follow-up plan with your genetic counselor to stay in touch while you're waiting for the results. Support groups or other types of counseling might be helpful, too.

What happens if the test result is negative?

A negative test result often provides peace of mind. It's important to know what the negative result means, however. Sometimes a negative result offers clarity and strong reassurance. In other cases, a negative result might lead to continued observation or more testing.

Let's say you have a family history of breast cancer but you test negative for the known genetic mutations associated with an increased risk of developing breast cancer. The genetic testing may ease your fears about breast cancer, but it doesn't offer any guarantees. Your risk is simply the same as that of the general population. A healthy lifestyle and regular cancer screenings remain important.

Also remember that individual genes are only part of the puzzle. A negative result can be reassuring, but it doesn't guarantee that you won't develop a disease. Sometimes a disease that runs in a family may be the result of shared environmental conditions, not genetics. In other cases, interactions among several genes or lifestyle factors may be responsible for a disease.

What happens if the test result is positive?

A positive test result can be frightening. However, it's important to understand what the positive result means. A positive result doesn't necessarily mean that you'll develop a disease, nor does a positive result predict the severity of the disease.

You might consider a positive result as an incentive to monitor your health more closely, make lifestyle changes or begin treatment as soon as possible. You might even take preemptive measures, such as a preventive mastectomy to reduce the risk of developing breast cancer. Even if there's no way to prevent or treat the disease, it's important to take steps to protect your health — such as eating healthy foods, exercising regularly, managing stress and seeing your doctor for regular checkups.

A positive result might also provide the incentive for other family members to consider genetic testing.

How will I know what the test results mean for me?

Genetic testing results can be interpreted differently depending on the circumstances. Your genetic counselor will consider your medical and family history when interpreting your test results, and help you understand what the results mean to you. You'll learn what the test results can — and can't — tell you about the future.

What if someone in my family doesn't want me to have genetic testing?

Genetic testing can be stressful. It's important to find someone close to you who can support you during the process. If you're getting resistance from someone in your family, you might dig a little deeper to find out what's behind the resistance. You can't change how someone else feels, but you can try to understand. If necessary, your genetic counselor can help you facilitate the discussion and reach common ground with your loved one.

Could genetic discrimination be a concern?

Although genetic discrimination is generally only a theoretical risk, the risk remains. If you're concerned about genetic discrimination and the possible effects on your insurance coverage or employment, share your fears with your genetic counselor. The possibility of genetic discrimination may play a role in your decision to pursue genetic testing.

Is genetic testing expensive?

The cost of genetic testing varies greatly, from hundreds to thousands of dollars. Insurance coverage for genetic testing varies, too. If you're concerned about the cost of genetic testing, consult your genetic counselor. He or she might facilitate a conversation with the insurance company or offer other suggestions on payment options.

What if I don't understand what's happening?

Don't be afraid to ask questions at any point. Your genetic counselor is there to educate you about genetic conditions and to help you make an informed decision about genetic testing. Count on your genetic counselor to address your concerns and support your wishes as he or she walks you through the process.