Genomic Testing

Genomic Tests by Levels of Evidence

Genetic tests have been developed for more than 2,200 diseases, of which about 2,000 are currently available for use in clinical settings. Most tests look at single genes and are used to diagnose rare genetic disorders, such as Fragile X Syndrome and Duchenne Muscular Dystrophy. In addition, some genetic tests look at rare inherited mutations of otherwise protective genes, such as BRCA1 and BRCA2, which are responsible for some hereditary breast and ovarian cancers.  However, a growing number of tests are being developed to look at multiple genes that may increase or decrease a person’s risk of common diseases, such as cancer or diabetes. Such tests and other applications of genomic technologies have the potential to help prevent common disease and improve the health of individuals and populations. For example, predictive gene tests may be used to help determine the risk of developing common diseases, and pharmacogenetic tests may be used to help identify genetic variations that can influence a person’s response to medicines. There is much we still need to learn about how effective these new tests are, and the best way to use them to improve health. Learn more.  

Limited Scientific Information for Most Genetic Tests

Despite the many scientific advances in genetics, researchers have only identified a small fraction of the genetic component of most diseases. Therefore, genetic tests for many diseases are developed on the basis of limited scientific information and may not yet provide valid or useful results to individuals who are tested. However, many genetic tests are being marketed prematurely to the public through the Internet, TV, and other media. This may lead to the misuse of these tests and the potential for physical or psychological harms to the public. At the same time, valid and useful tests, such as those for hereditary breast and ovarian cancer or for Lynch syndrome, a form of hereditary colorectal cancer, are not widely used, in part because of limited research on how to get useful tests implemented into practice across U.S. communities. Individuals can learn more about specific genetic tests by visiting the Web sites listed below or by talking with their doctor.

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The Need for Reliable Information on Genetic Testing

In 2008, the former Secretary's Advisory Committee on Genetics, Health and Society of the U.S. Department of Health and Human Services released a report identifying gaps in the regulation, oversight, and usefulness of genetic testing. They expressed the need for timely, reliable information that health care providers, payers, public health practitioners, policy makers, and consumers could use to make more informed decisions about the appropriate use of these tests in clinical and public health practice.

To begin addressing this need for reliable information, CDC’s Office of Public Health Genomics (OPHG) established the Evaluation of Genomic Applications in Practice and Prevention (EGAPP™) Initiative project to systematically evaluate genetic tests and other applications of genomic technology that are in transition from research to clinical and public health practice. Since 2005, the independent EGAPP Working Group has released six recommendations on the validity and utility of specific genetic tests. Read CDC Summaries of EGAPP Recommendations.

The U.S. Preventive Services Task Force (USPSTF) has also released recommendations on specific genetic tests used in selected clinical scenarios involving breast cancer, colorectal cancer, and hemochromatosis.

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Learn More About Genetic Testing

For Consumers

• Genetic Testing: What you need to know [755.15 KB], CDC’s Laboratory Science, Policy, and Practice Program Office
• Frequently Asked Questions About Genetic Testing, National Institutes of Health
• What is Direct-to-Consumer Genetic Testing? Genetics Home Reference

For Health Professionals

• CDC Podcast on Personal Genomic Tests, Dr. Muin J. Khoury, Director of CDC's Office of Public Health Genomics
• Health Professionals and Genetic Testing: What you need to know [PDF 140.18 KB], CDC’s Laboratory Science, Policy, and Practice Program Office
• GeneTests
• U.S. System of Oversight of Genetic Testing: A Response to the Charge of the Secretary of Health and Human Services, Report of the Secretary's Advisory Committee on Genetics, Health, and Society [2.10 MB]
• Secretary's Advisory Committee on Heritable Disorders in Newborns and Children, U.S. Department of Health and Human Services Health Resources and Services Administration (HRSA)
• Genetic Testing Registry, National Institutes of Health
• U.K. National Institute for Health and Clinical Excellence (NICE)

Also see the genetic testing and genetic counseling sections of CDC’s Office of Public Health Genomics’ resource guide.

Other CDC Activities

• ACCE Model Process for Evaluating Genetic Tests
• GAPP Knowledge Base
• PloS Currents: Evaluation on Genomic Tests
• Genomic Applications in Practice and Prevention Network (GAPPNet™)
• Knowledge Synthesis Center for Genomic Applications, Center for Health Research Northwest, Kaiser Foundation Hospitals, Portland, Oregon

• Laboratory Practice Evaluation and Genomics Branch, CDC
• Newborn Screening and Related Conditions, CDC

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