Can Home DNA Tests Be Wrong?

May 20, 2018

Contrary to popular belief, there’s a big difference between home and at-home (direct-to-customer) DNA tests. Home DNA tests are testing solutions you can buy at your local pharmacy and do the testing in its entirety in the privacy of your home, which includes generating the final results. At-home DNA tests, on the other hand, are testing solutions where only your sample collection is performed at home while the sequencing process is done in a professional lab. Needless to say, we will be covering the latter iteration. 

We’ve already dispelled one of the most common myths surrounding direct-to-customer DNA testing. Yes, they are also done in a highly specialized laboratory, so the only difference between at-home DNA tests and tests performed in a hospital is in the sample collection procedure. 

With that cleared, we can start talking about the overall accuracy of at-home DNA tests and their potential for errors. 

Can Home DNA Tests Be Wrong

At-Home DNA Tests – Error Margins

At-home DNA testing is performed by highly qualified scientists in CLIA-certified labs, the testing solutions offered by renowned companies are FDA-approved, and every procedure prescribed by the state and relevant institutions is followed to the letter. Therefore, these tests and procedures follow the same rules and offer the same quality as tests performed in hospitals, clinics, and similar facilities. This means that the accuracy and error margins of the tests basically depend on the current reach and development of genetic science. In other words, we are interested in discovering whether the DNA testing solutions we currently have at our disposal are infallible or still have some potential for errors.

Different DNA testing solutions offer different numbers and success rates. For example, with relationship DNA testing (paternity, maternity, siblings…), the inclusion accuracy factor is 99.99% with good companies. If the test confirms the existence of a specific biological relationship between the subjects, this result is 99.99% accurate. Exclusion or negative results are always 100% accurate.

At-Home DNA Tests – Error Margins

When it comes to ancestry DNA testing, renowned companies usually check more than 500,000 genetic markers in your genome and compare the results with hundreds of thousands of unique genetic signatures in their databases. Keep in mind that the only difference in the DNA of all people in the world lies in their specific genetic mutations or SNPs (single nucleotide polymorphisms). If enough of these mutations match between two genetic signatures, we have a very high probability of a genetic relationship and common ancestry. The accuracy of ancestry DNA tests starts at 97%. 

Health-related DNA tests simply check your genome for mutations connected to predispositions for certain genetic illnesses. There’s basically no room for errors there. Either the mutation of the specific gene is there or it’s not. 


So, can (at-home) DNA tests be wrong? 

Essentially, yes. But the possibility of error is so small, it’s borderline irrelevant. The more important point is that there is no disparity in the overall quality of DNA tests performed in hospitals or ordered online from reputable companies. At-home DNA tests are extremely accurate and you don’t have to worry about the validity of your final report as long as you opt for one of the many proven and reputable companies currently on the market.

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