How Does A Home DNA Test Work?

Home DNA tests have exploded in popularity in recent years. The convenience of being able to perform the test in your own home has meant that it is now more accessible. 

They are available for purchase online and in some drugstores. Some tests will specify that the subject must be at least 18 years old, although this is not always the case. In some cases, if a minor wishes to conduct the test, the genetics company will require some signed parental consent. 

How Does A Home DNA Test Work

Why would you need a DNA test?

You may want to trace your family genealogy to find out more about your past. You may need to get a paternity test for a child. DNA tests are also performed to test for your individual risk factors for health issues and diseases. They can also be used to check your levels of fitness and nutrition. 

Your DNA holds all of your personal information, and so you can find out almost anything from it. Some DNA tests will show you what your heritage is, while others will indicate food allergies and sensitivities. 

What happens during the test?

In order to get the most accurate results, we recommend performing your home DNA test first thing in the morning. You should not have anything to eat or drink and ideally will not have brushed your teeth yet.

You will receive a sterilized and a hermetically sealed cotton swab in the post. You will need to open this and rub the cotton tip around the inside of your cheek. This collects a layer of saliva and epithelial cells on the swab. 

You will then need to seal the swab inside a sterilized tube and snap off the stick. Fill out the corresponding form and post it to a laboratory in order to be tested.

You may purchase a test that requires a saliva sample. In this case, all you will need to do is dribble into a tube and send that off. More rarely, genetics companies may ask you to send in a blood sample. If this is the case, you will need to use a finger prick and drip some blood into the desired sample tube. 

You are likely to have some kind of unique reference or identification number that comes alongside your test. This will need to be registered online so that the laboratory can tell who the sample belongs to. 

What happens after the test? 

The laboratory will analyze and interpret the results of your DNA test. It is likely to take around 10 - 14 working days to receive your results. 

The laboratory will extract the DNA from the cells in your salivary or blood sample. It is then amplified - this means that it is copied hundreds of times so that it is easier to analyze. This is done through a process known as genotyping.

A genotype is your individual DNA sequence. Genotyping is a process where scientists compare your genotype with a reference sequence. They look for differences and similarities in these sequences. This will indicate a number of things, from height and appearance to risk factors for certain diseases. 

To genotype your DNA, it is cut into small pieces once it has been amplified. These small sections are placed onto a Microarray - a small glass slide with millions of microscopic beads.

These beads are attached to a probe that is designed to find the genetic variants that are being tested for. Essentially, the cut sections of DNA stick to the corresponding probes on the Microarray. 

There are 4 bases that make up DNA - Adenine, Cytosine, Guanine, and Thymine. The different combinations of bases dictate different characteristics. The Microarray chip is designed to highlight specific base sequences. 

Are they accurate?

Provided you perform the test correctly, home DNA tests are accurate. Eating immediately before swabbing your mouth may skew the results and provide you with inaccurate results. 

You should look for home DNA tests from reputable testing companies to ensure the most accurate results. The tests from reputable companies will clearly tell you which laboratory does the analysis. If it does not mention one, we suggest using a different supplier. 

Health DNA tests are regulated by the FDA in the United States. They are measured using something known as Sanger sequencing. DNA tests must be at least 95% concordant with this sequencing. 

What are reputable DNA testing companies?

You should look at the company’s self-regulating policies before purchase. They are legally obligated to protect your genetic data. A reputable company will clearly state their privacy and data protection policies.

Most home DNA companies have an opt-in policy that allows your data to be shared with researchers in order to further medical knowledge. They are not allowed to do this without your explicit consent, as this would be a breach of privacy regulations. 

There is one exception to this, which is law enforcement. DNA companies do not have to comply with requests from the police, but as soon as a court order is issued they must do as it states. You can request the deletion of your DNA from the genetics testing service.

If your data has already been shared with a third party, you will be unable to recall this. 

DNAFit is a genetics company that focuses on testing for diet and fitness markers in your DNA. This information can then be used to improve your diet and cater fitness plans to you. 

HomeDNA has clearly published privacy and data protection policies on its website. They are closely linked to a lab and seem to be a very reliable company. 

23andme has Clinical Laboratory Improvement Amendments (CLIA) certified and Certified Authorization Professional (CAP) accredited laboratories. This means that there are rigorous standards that the laboratories must meet, giving you confidence in their validity.

23 and Me

AncestryDNA has supplied in excess of 15 million home DNA kits. They state that their policy requires a search warrant or court order to be supplied before any consumer information is revealed to investigators. 

There has been a body created through collaborative working of Ancestry, 23andMe, and Helix, known as the Coalition for Genetic Data Protection. This was created to petition for a “reasonable and uniform privacy regulation that will ensure the responsible and ethical handling of every person’s genetic data.”

There is also a non-profit organization known as the Future of Privacy Forum. Ancestry, 23andMe, Helix, MyHeritage, Habit, Living DNA, and African Ancestry have collaborated with this company. They are trying to create a list of best practices concerning the genetic testing services. This is rooted in improving process transparency and giving consumers more control over how their data is collected and used. 

Any of the companies that we have mentioned here are reputable and you should have no concerns about the way that they handle your personal data once it’s been sent.

How much do home DNA tests cost?

This will vary between providers. Bear in mind that you are not just paying for the sample equipment and test kit. Your money is also being used to fund the laboratory analysis and the cost will vary depending on the purpose of the test. 

Paternity tests are likely to set you back between $130 and $200 for home tests. If you wish to use the results in court, this will add to the cost. These kinds of tests are likely to cost between $300 and $500. 

Ancestry and genealogy DNA tests range from a budget option at only $49 to over $200. This varies depending on the amount of information you require. 

There are many other types of DNA tests available too. These include maternity tests, grandparent tests, sibling tests, aunt/uncle tests, family reconstruction, and twin zygosity. 

Maternity tests tend to be used in adoption and immigration cases and will cost around $200 to $450. 

Grandparent tests are used when the assumed biological father is not available for DNA testing. The paternal grandparent DNA results are compared to DNA samples from the mother and child. This will either prove or disprove a biological link, and tends to cost $300 to $500. 

Sibling DNA tests are used to establish a relationship between siblings. These tests are again mostly used in cases of immigration and disputed inheritance. These too, will set you back $300-$500.

The aunt/uncle tests are compared to the DNA of the alleged niece or nephew. This will either establish or disprove a genetic relationship. These tests also cost $300 to $500. 

Family reconstruction tests sample a range of close family members to fully understand the biological relationships between everyone. This is commonly used in the case of unclear paternity. These will cost around $450 to $650. 

A twin zygosity test will tell the parents whether their twin children are identical or fraternal. Identical twins are formed when one egg is fertilized and splits into 2. Fraternal twins come from 2 separate fertilized eggs and often develop in separate amniotic sacs. This test will cost $250.