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

Direct-to-consumer genetic testing can provide information about your health, traits, and ancestry. However, the standards and guidelines for these tests are different than those that are used for clinical genetic testing or provider-driven genetic testing. Direct-to-consumer tests are often for information purposes only—they are generally not meant to diagnose, prevent, or treat a disease or health condition. It is useful to keep these distinctions in mind when reviewing your own test results.

Direct-to-consumer genetic testing companies use specific methods to analyze their large datasets of genetic variants to predict the likelihood of certain health outcomes. The results typically do not give a “yes or no” answer about whether a person has a specific trait or will develop a given disease. Instead, they often provide an estimate of how likely a person is to have that trait or develop that condition. Direct-to-consumer genetic testing companies may provide updates (sometimes for a fee) to a person’s results as research and technology improves.

Here are the kinds of results you might receive from the different types of direct-to-consumer genetic tests available:

Carrier or disease risk tests

The results of carrier or disease risk tests generally indicate how specific genetic variants may impact disease risk or how likely someone is to pass those variants on to their children.

Carrier and disease risk tests look at variants that are known or suspected to be associated with a particular disease and how that variant may impact the risk of developing the disease. Carrier tests identify gene variants that can cause a genetic disorder when they are present in both copies of a specific gene. Direct-to-consumer genetic tests often do not look at all genetic variants or factors that are associated with developing diseases such as cystic fibrosis, Alzheimer’s disease, or different forms of cancer. A result that shows an increased risk of a specific disease does not mean that a person will definitely develop the disease, and a result that shows a reduced risk does not mean that a person will never develop the disease. Being a carrier for a disease does not mean that a person has the disease, but if their partner is also a carrier, it can impact their children’s risk of developing the disease.

People whose tests results indicate a positive result or an increased risk for developing a disease may benefit from speaking with a genetic counselor or other healthcare professional.

Pharmacogenomic tests

Pharmacogenomic tests analyze specific genetic variants and provide insights into how these variants might affect an individual’s response to medications.

The results of pharmacogenomic tests provide information about how a person may respond to certain medications (pharmacogenomics). Specifically, the results make predictions about how specific genetic variants impact an individual’s ability to break down (metabolize) medications. Generally, people can be slow, normal, or fast metabolizers. Several genes can be involved in determining how the body reacts to certain medications. As a result, changes in one gene may make a person a fast metabolizer of one drug, while changes in a different gene can make them a slow metabolizer of another drug. Many other factors, including sex, age, weight, diet, and the use of other medications, also play a role in determining how the body responds to drugs.

Trait tests

The results of traits tests can predict the likelihood that a person has certain traits, but these tests may not account for all of the factors that influence these traits.

The results of traits tests can predict the likelihood that a person has particular traits (such as cheek dimples or a certain eye color). These tests analyze certain genetic variants, but they do not take into account all of the factors that influence the development of a particular trait. As a result, the results may not always be accurate. For example, a person with cheek dimples might get results that say they are likely not to have cheek dimples.

Lifestyle tests

The results of lifestyle tests provide predictions about certain aspects of health, such as nutrition, fitness, and sleep, based on an analysis of genetic variants.

In most cases, direct-to-consumer lifestyle tests assess genetic variants that are related to factors such as nutrition (also known as nutrigenomics), fitness, or sleep. The results of these tests will suggest how likely a person is to have a certain characteristic, such as a specific food sensitivity. The company may recommend personalized diet or fitness programs, dietary supplements, skincare products, or other products and services based on the results. However, in most cases the link between a given genetic variation and a complex trait like weight, athletic performance, or sleep is complicated. It can be difficult to predict the significance of the results.

Ancestry tests

The results of ancestry tests offer clues about ancestral geographic origins based on genetic variants. The results are presented as percentage breakdowns and may include maps and chromosome diagrams.

The results of ancestry tests give clues about major geographic areas where a person’s ancestors may have lived. The results are calculated by comparing an individual’s results to a reference database of genetic variations from people whose ancestry is known. The results are often presented as a percentage breakdown, ordered from the highest proportion to the lowest (sometimes as low as less than 0.1%). This percentage breakdown is also shown on a map of the world and a diagram of the person’s chromosomes.

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

Kinship tests

Kinship tests provide results about likely biological relationships based on DNA similarities.

The results of kinship tests give information about the potential genetic relationships between individuals who have undergone testing based on similarities in their DNA sequences. These tests can uncover previously unknown biological relationships, such as paternity. 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.

Raw Data

Some direct-to-consumer genetic testing companies make your raw genotype data available for download. Interpreting this data independently is challenging, and privacy measures should be considered when using third-party services.

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. Once the raw data is downloaded, it is no longer protected by the original service’s privacy measures. It is challenging to interpret raw genotype data on your own. If you choose to use a different company (third party service) to analyze your raw data, it is important to assess the credibility of the company and to determine how they will analyze your data and how they will protect your privacy before sharing your genetic information.

Additional information

To read about genetic diseases and their causes, MedlinePlus provides in-depth information about many of the conditions and genes that are included in direct-to-consumer genetic testing reports.

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 receiving the results of a direct-to-consumer genetic test.