Genetic testing involves examining your DNA, the chemical database that carries instructions for your body's functions. Genetic testing can reveal changes or alterations in your genes that may cause illness or disease.
Although genetic testing can provide important information for diagnosing, treating and preventing illness, there are limitations. For example, if you're a healthy person, a positive result from genetic testing doesn't always mean you will develop a disease. On the other hand, in some situations, a negative result doesn't guarantee that you won't have a certain disorder.
Talking to your doctor or a genetic counselor about what you will do with the results is an important step in the process of genetic testing.
Why it's done
Several types of genetic testing are done for different reasons:
How you prepare
Before you undergo genetic testing, gather as much information as you can about your family's medical history. Then, talk with your doctor or a genetic counselor about your personal and family medical history. This will help you better understand your risk. Discuss any questions or concerns you have about genetic testing at that meeting. Also, talk about your options, depending on the results of the test.
If you are being tested for a genetic disorder that runs in families, you may want to consider discussing your decision to undergo genetic testing with your family. Having these conversations before testing can give you a sense of how your family might respond to your test results and how it will affect them.
Not all health insurance pays for genetic testing. So, before you have a genetic test, check with your insurance provider to see what will be covered. In the United States, the federal Genetic Information Nondiscrimination Act (GINA) helps prevent health insurers or employers from discriminating against you based on test results. Most states offer additional protection.
What you can expect
Your doctor, medical geneticist or nurse practitioner may select, order or administer a genetic test. A sample of your blood, skin, amniotic fluid or other tissue will be collected and sent to a lab for analysis.
The amount of time it takes for you to receive your genetic testing results will depend on the type of test and your health care facility. Talk to your doctor before the test about when you can expect the results. The lab will likely provide the test results to your doctor in writing. Your doctor can then discuss them with you.
If you were tested to find out if you are carrying an altered gene that could cause disease in your child, and the test is positive, your doctor or a genetic counselor can help you determine a child's risk of actually developing the disease. The test results can also provide information to consider as you and your partner make family planning decisions.
If you were having gene testing to determine if you might develop a certain disease, a positive test doesn't necessarily mean you will get that disorder. For example, having a breast cancer gene (BRCA1 or BRCA2) means you are at high risk of developing breast cancer at some point in your life, but it doesn't indicate that you will get breast cancer. However, there are some conditions, such as Huntington's disease, for which the altered gene does indicate that the disease will eventually develop.
Talk to your doctor about what a positive result means for you. In some cases, you can make lifestyle changes that may decrease your risk of developing a disease, even if you have an altered gene that makes you susceptible to a disorder. Results may also help you make choices related to family planning, careers and insurance coverage.
In addition, you may choose to participate in research or registries related to your genetic disorder or condition. These options may help you stay updated with new developments in prevention or treatment.
Even if you don't have the genetic alteration, that doesn't necessarily mean you will never get the disease. For example, people who don't have a breast cancer gene (BRCA1 or BRCA2) can still develop breast cancer. Also, genetic testing may not be able to detect all genetic defects.
No matter what the results of your genetic testing, talk with your doctor or genetic counselor about questions or concerns you may have, so you understand what the results mean for you and your family.
Last Updated: 2011-01-07
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