A doctor's recommendation is not needed to use a direct-to-consumer (DTC) home genetic testing kit.
The person self-submits a tissue sample to a laboratory and receives the results by phone or email.
Genetic testing can show how likely someone is to develop a particular condition, or to pass a condition along to their children.
Until recently, kits were mainly used to demonstrate paternity of a child or to identify genealogical ancestry.
In 2015, one kit was approved by the United States (U.S.) Food and Drug Administration (FDA) to test for a medical condition known as Bloom syndrome. In 2017, a test was approved for further conditions.
How useful a test is will depend on the condition being tested for, how the test is carried out, and the integrity and credentials of the laboratory performing the test.
Here are some facts about at-home genetic testing. More information is in the main article.
- At-home genetic testing kits are available in mainstream pharmacies and online.
- Prices range from several hundred to over one thousand dollars.
- In 2015, the FDA approved the first testing kit relating to inherited medical conditions.
- Kit users normally send a saliva sample to a lab, and then wait for the results.
- A positive result does not mean a disease will occur. Some conditions will only develop if triggered by environmental factors.
What is an at-home genetic test?
Genetic testing can identify ancestry, paternity, or predispositions toward certain conditions.
At-home genetic tests are available over-the-counter (OTC) at some pharmacies or online from the manufacturer or a retailer.
Prices can range from several hundred to over a thousand dollars.
In April 2017, the FDA ruled that 23andme, a genetic testing laboratory that provides at-home kits, can test for a number of genetic conditions.
This ruling reversed the FDA's 2013 ban on this kind of testing and opened up the possibility of at-home genetic testing kits providing advice on specific medical conditions rather than non-clinical information, such as family ancestry.
Previous fears were that customers might misinterpret the results and that they could be exploited through advertising.
How do they work and why would you need one?
After purchasing the test, the person normally has to salivate, or spit, into a container. Then, they mail the container directly to the laboratory for analysis.
The tests work by the subject providing a saliva sample, which is then sent to the laboratory for analysis by a genetic specialist.
With some kits, the person needs to attend a clinic to provide a blood sample instead of saliva.
The pack will normally contain a pre-paid envelope to enable the straightforward submission of the sample.
At the laboratory, a pathologist or lab technician can detect whether the sample contains a genetic feature that might cause or increase the risk of a specific condition.
Consumers may obtain their results online or by phone. A genetic counselor is sometimes provided to explain the results.
This may be useful for a person who has a family member with a condition that could be genetic in nature, such as Alzheimer's disease or breast cancer. If a person knows they are at risk, they can take preventive measures.
What do at-home genetic tests diagnose?
Genetic testing can reveal information about a range of conditions resulting from genetic mutations.
A mutation may be passed on though parents' inherited genes, or it may occur at conception, when the egg and sperm meet.
The genetic conditions that can currently be tested for are:
- Bloom syndrome
- Parkinson's disease
- late-onset Alzheimer's disease
- Alpha-1 antitrypsin deficiency, which can lead to lung and liver disease
- early-onset primary dystonia, a movement disorder
- factor XI deficiency, a blood-clotting disorder
- Gaucher disease type 1, an organ and tissue disorder
- glucose-6-phosphate dehydrogenase deficiency, a red blood cell condition
- hereditary hemochromatosis, an iron overload disorder
- hereditary thrombophilia, a blood clotting disorder
These are serious conditions. Before doing the test, users have to click to acknowledge that they understand the results could lead to anxiety.
It is important to note that a positive result does not mean that a disease will develop. Many conditions need both genetic and environmental or lifestyle factors to develop.
Coronary heart disease, for example, can be inherited, but a poor diet, inactive lifestyle, and smoking increase the risk.
Risks and cautions
The Clinical Laboratory Improvement Amendments (CLIA) regulate in-clinic genetic testing to ensure that three conditions are met.
23andme have manufactured the first at-home genetic testing kit to receive FDA approval for advising of the likelihood of specific conditions.
These relate to:
- Analytical validity: Is the test accurate at noting the presence or absence of a particular gene?
- Clinical validity: How well does the absence or presence of a gene link to the specific disease?
- Clinical utility: Will this test provide useful or disease-preventing advice to the consumer?
CLIA approval ensures that the lab results are being processed under satisfactory conditions for an accurate reading.
FDA approval regulates the consumer rights aspects of genetic testing.
CLIA alone does not guarantee that the manufacturer follows advertising standards, or that the test will be clinically relevant to an individual's state of health, only that the processing is correct.
Not all genetic testing packs are regulated by both the CLIA and the FDA. The test pack should be correctly accredited by both, if used for medical testing.
Genetic tests are expensive, and consumers need to be sure they know what they are getting. Widespread regulation is needed to ensure the tests are accurate and to prevent misleading marketing.
In addition, the prognosis provided by an at-home genetic testing kit is not yet sufficiently reliable for people to base a preventive action plan on it.
If an incorrect result suggests a person is at risk of a genetic disease, they may worry unnecessarily. Conversely, they may neglect to take preventive action if they get a false negative result.
If there is a good chance that a genetic issue is present, for example, if several family members have the same condition, it is probably best to visit a qualified genetic medical specialist.
Another issue in the past has been that companies have shared personal or genetic information without permission. Controls should be in place to ensure that information remains confidential.
"It is important that people understand that genetic risk is just one piece of the bigger puzzle, it does not mean they will or won't ultimately develop a disease.."
Dr. Jeffrey Shuren, director of the FDA's Center for Devices and Radiological Health
For those who do opt for a home test, the National Institute of Health's Genetic Testing Registry can help decide which type of kit is most suitable.
Research has not yet shown whether knowing about a possible genetic condition can enable its prevention.