What is genetic testing?

Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder. More than 1,000 genetic tests are currently in use, and more are being developed.

Several methods can be used for genetic testing:

• Molecular genetic tests (or gene tests) study single genes or short lengths of DNA to identify variations or mutations that lead to a genetic disorder.

• Chromosomal genetic tests analyze whole chromosomes or long lengths of DNA to see if there are large genetic changes, such as an extra copy of a chromosome, that cause a genetic condition.

• Biochemical genetic tests study the amount or activity level of proteins; abnormalities in either can indicate changes to the DNA that result in a genetic disorder. 

Genetic testing is voluntary. Because testing has benefits as well as limitations and risks, the decision about whether to be tested is a personal and complex one. A geneticist or genetic counselor can help by providing information about the pros and cons of the test and discussing the social and emotional aspects of testing.

For general information about genetic testing:

MedlinePlus offers a list of links to information about genetic testing.

The National Human Genome Research Institute provides an overview of this topic in its Frequently Asked Questions About Genetic Testing. Additional information about genetic testing legislation, policy, and oversight is available from the Institute.

The National Institutes of Health fact sheets Genetic Testing: What It Means for Your Health and for Your Family’s Health and Genetic Testing: How it is Used for Healthcare each provide a brief overview for people considering genetic testing.

Educational resources related to genetic testing are available from GeneEd.

The Genetics and Public Policy Center also offers information about genetic testing.

You can also search for clinical trials involving genetic testing. ClinicalTrials.gov, a service of the National Institutes of Health, provides easy access to information on clinical trials. You can search for specific trials or browse by condition or trial sponsor. You may wish to refer to a list of studies related to genetic testing that are accepting (or will accept) participants.

Next: What are the types of genetic tests?