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 the genetic test result is positive, that means the genetic alteration that was being tested for was detected. The steps you take after you receive a positive result will depend on the reason you underwent genetic testing. If the purpose was to diagnose a specific disease or condition, a positive result will help you and your doctor determine the right treatment and management plan.
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 your 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 with certainty that you will get breast cancer. However, there are some conditions, such as Huntington's disease, for which having 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 more 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.
A negative result means a genetic alteration was not detected by the test. But a negative result doesn't guarantee that you don't have an alteration. The accuracy of genetic tests to detect alterations varies, depending on the condition being tested for and whether or not an alteration has been previously identified in a family member.
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.
In some cases, a genetic test may not be able to provide helpful information about the gene in question. Everyone has variations in the way genes appear (polymorphisms), and often, these variations don't affect your health. But sometimes it can be difficult to distinguish between a disease-causing gene alteration and a harmless gene variation. In these situations, follow-up testing may be necessary.
No matter what the results of your genetic testing, talk with your doctor or genetic counselor about questions or concerns you may have. This will help you understand what the results mean for you and your family.
July 19, 2013
- Handbook — Help me understand genetics. Genetics Home Reference. http://ghr.nlm.nih.gov/handbook/. Accessed May 7, 2013.
- Frequently asked questions about genetic testing. National Human Genome Research Institute. http://www.genome.gov/19516567. Accessed May 7, 2013.
- Raby BA, et al. Genetic counseling and testing. http://www.uptodate.com/home. Accessed May 8, 2013.
- Grody WW, et al. ACMG position statement on prenatal/preconception expanded carrier screening. American College of Medical Genetics and Genomics. Genetics in Medicine. In press. Accessed May 8, 2013.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. May 10, 2013.