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How is direct-to-consumer genetic testing done?

How is direct-to-consumer genetic testing done?

For most types of direct-to-consumer genetic testing, the process involves:

1. Purchasing a test
Test kits can be purchased online (and are shipped to your home) or at a store. The price of some test kits includes the analysis and interpretation, while in other cases this information is purchased separately.
2. Collecting the sample
Collection of the DNA sample usually involves spitting saliva into a tube or swabbing the inside of your cheek. You then mail the sample as directed by the company. In some cases, you will need to visit a health clinic to have blood drawn.
3. Analyzing the sample
A laboratory will analyze the sample to look for particular genetic variations. The variations included in the test depend on the purpose of the test.
4. Receiving results
In most cases, you will be able to access your results on a secure website. Other test companies share results in the mail or over the phone. The results usually include interpretation of what specific genetic variations may mean for your health or ancestry. In some cases, a genetic counselor or other healthcare provider is available to explain the results and answer questions.

The test kit will include step-by-step instructions, so be sure you understand them before you begin. If you have questions, contact the company before collecting your sample.

How much does direct-to-consumer genetic testing cost, and is it covered by health insurance?

The price of direct-to-consumer genetic testing ranges from under a hundred dollars to several thousand dollars. The cost depends on how many genetic variations are analyzed (and it will cost more if whole genome or whole exome sequencing is used), how extensive the interpretation of results is, and whether other products, programs, or services are included. Some companies charge separately for the sample collection kit and the analysis, while others offer the sample collection and analysis as part of a package.

In some cases, consultation with a healthcare professional (such as a genetic counselor) is included in the cost of testing; in others, it can be added for an additional fee. Before you proceed with testing, make sure you know the total cost for all of the results, support, and other services you expect to receive.

Direct-to-consumer genetic tests, even tests that provide information about health and disease risk, are not covered by most health insurance plans. Because this testing is done without a referral from a healthcare provider and is not considered “diagnostic” (that is, it cannot be used to diagnose any disease or condition), health insurance companies generally will not pay for it. However, if you share your results with your healthcare provider and he or she recommends additional testing or management, that follow-up care may be covered.

Direct-to-consumer genetic tests that are unrelated (or indirectly related) to health, such as ancestry testing and paternity testing, are typically not covered by health insurance plans.

What do the results of direct-to-consumer genetic testing mean?

Direct-to-consumer genetic testing can provide interesting information about your health, traits, and ancestry. However, the results may not be as clear-cut as many people assume. Companies that provide these tests often tell their customers that the results are for information, education, and research purposes only—they are not meant to diagnose, prevent, or treat any disease or health condition. It is useful to keep this distinction in mind when interpreting your own test results.

Health and disease risk

The results of these genetic tests provide information about your chance of developing certain diseases and the likelihood that you have particular traits (such as dimples or lactose intolerance). These results are usually based on an analysis of one or more genetic variations that are known or suspected to be associated with the disease or trait.

The results of tests to predict disease risk do not provide a “yes or no” answer about whether a person will develop a given disease. Other factors, including genetic variations that were not tested, environmental factors, and lifestyle choices (such as diet and exercise) also contribute to disease risk in ways that may not be fully understood. Therefore, a result showing an increased risk does not mean you will definitely develop the disease, and a result showing a reduced risk does not mean you will never develop the disease.

Ancestry

The results of these tests give clues about major geographic areas that are your family’s origins. These results are calculated on the basis of genetic variations that are more common in people from certain areas of the world than in others. You may also choose to receive information about individuals who are likely related to you. (These individuals have also undergone testing, and the predictions are based on similarities among DNA sequences.)

Sometimes the results of ancestry testing are unexpected or inconsistent with what a person understands about his or her family history. These tests can uncover previously unknown information about biological relationships among people (such as paternity). People who are closely related, such as siblings, may receive slightly different information about their ancestry because results are limited by the number and diversity of people who have submitted DNA samples to a given direct-to-consumer genetic testing company.

It is important to be aware that receiving unexpected or ambiguous information about your background or family is a potential risk with this type of testing.

Lifestyle

In most cases, direct-to-consumer lifestyle tests assess genetic variations related to very specific traits, such as how your body converts the nutrients from food into energy (metabolism), day/night (circadian) rhythm, or the senses of taste and smell. The company may recommend specific diet or fitness programs, dietary supplements, skincare products, or other products and services on the basis of your results. However, in most cases the link between a given genetic variation and a complex trait like weight, athletic performance, or sleep is indirect or unknown.

Therefore the results of these tests can be challenging to interpret, and it can be difficult to predict whether a recommended product or service will be helpful to you.

If you have questions about the meaning of your test results, professional support (such as guidance from a genetic counselor) may be available from the company that provided the test. You can also share questions about your results with your own healthcare provider. Talk to your doctor before making any major changes in managing your health, diet, or fitness after you receive results of a direct-to-consumer genetic test.

What can raw data from a direct-to-consumer genetic test tell me?

In addition to providing various reports and analyses based on your genetics, some direct-to-consumer genetic testing companies make your raw data available to download. The raw data are your genotype—the particular A’s, C’s, T’s, and G’s of your DNA—extracted from the sample you provided. These data are unique to you. Most companies caution that the raw data are only for research or education and are not suitable for medical purposes, such as diagnosing a disease.

It is challenging to interpret raw genotype data on your own. To help with this, several online “third-party interpretation” services offer analysis and interpretation of the raw data collected by another company. Third-party interpretation services can potentially use your genetic data to provide you with more information about your disease risk, traits, and ancestry. However, these services also have some risks and limitations:

  • Relatively often, test results include false positives, which means that the service indicates an increased risk of disease when your risk is not actually higher than that of the general population. False positives and other errors can cause stress and anxiety.
  • The results may include unexpected or upsetting information about your disease risk or family relationships without any context or guidance.
  • The raw data, once you download it and send it by e-mail or store it on your computer, is no longer protected by the original service’s privacy measures.
  • There is little regulation of third-party interpretation services.

As with any kind of genetic testing, it is important to assess the credibility of any company you are considering and find out how it protects your privacy before submitting your genetic information. Your healthcare provider can help you understand your results and determine whether any follow-up testing would be useful.

Can a direct-to-consumer genetic test tell me whether I will develop cancer?

While a direct-to-consumer genetic test can estimate your risk, it cannot tell you for certain whether you will or will not develop certain forms of cancer. Many other factors, including gender, age, diet and exercise, ethnic background, a history of previous cancer, hormonal and reproductive factors, and family history also contribute to a person’s overall cancer risk.

The U.S. Food and Drug Administration (FDA) has allowed at least one direct-to-consumer genetic testing company, 23andMe, to offer a test for cancer risk. The test looks for three specific variations in two genes: BRCA1 and BRCA2. These variations are associated with an increased risk of breast cancer, ovarian cancer, and potentially other forms of cancer in people of Ashkenazi (eastern European) Jewish ancestry.

Researchers estimate that 5 to 10 percent of all cancers run in families. Some of these cancers are associated with inherited mutations in particular genes, such as BRCA1 or BRCA2. More than 1,000 variations in each of these genes have been associated with an increased risk of cancer. However, the FDA-approved direct-to-consumer genetic test analyzes only three of these variations. The variations included in the test are much more common in people of Ashkenazi Jewish background than in people of other ethnicities, so if you are not of Ashkenazi Jewish heritage, the results may not be useful to you.

Because the variants included in the test are uncommon, most people will have a negative result. A negative result does not mean that you will never get cancer. Similarly, a positive result (one that indicates a cancer-related genetic variation) does not mean that you will definitely develop cancer.

Direct-to-consumer genetic testing for cancer risk can be stressful and anxiety-producing. Health professional organizations and patient advocacy groups strongly recommend that people considering genetic testing for BRCA1 and BRCA2 variations, including those included in direct-to-consumer genetic tests, talk with a genetic counselor about the reasons they want to undergo testing and what the results could mean for their health.

Source: https://ghr.nlm.nih.gov/primer 

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