DNA test accuracy

Can DNA testing be wrong?

What are the chances of a DNA test being wrong when consumer genetics and DNA testing companies have become so mainstream? These companies and their products keep making news headlines as well as appearing in all forms of media for different reasons. 

A lot of them tend to have mixed reviews while market leaders such as 23andMe and AncestryDNA, boast of more than five million users in their databases. Most people are only a few package deliveries away from finding out their ancestry or hidden truths in their ancestry. 

Deoxyribonucleic acid or DNA is the hereditary material found within cells of humans and almost all other organisms. It is a complex way the body stores information which determines so many aspects of our lives and sometimes even determines the disease that we might have. DNA is arranged as an estimated 20,000 genes and during birth. We inherit 23 pairs of chromosomes from our parents. As DNA is passed on it is reshuffled.

Therefore, since our genetic makeup affects everything from our health to diets, many people have caught on to the trend. They have gotten involved with the aim to have in-depth knowledge of themselves, their family relationships and their key insights into their origins. 

Most of these consumer DNA tests are advertised or branded as infallible. But is this the reality or just a marketing tool to get people to purchase their products? Can the various types of home DNA test kits ever be wrong – be it ancestry, paternity, or the many others out there?

Why do people trust DNA tests?

People trust DNA tests regardless of how often they believe home DNA test can wrong or inaccurate. At-home DNA tests are not a substitute for medical diagnosis. It is not intended for that purpose rather it is supposed to give some information to work with to understand the results. 

A reason why people trust DNA tests is because of Brand equity. A lot of people perceive these DNA testing companies, trustworthy scientific partners. Companies such as 23andMe, Ancestry, and MyHeritage are pretty well respected and have tons of good reviews by the general public.

When the issue of ancestry and family relationships arises, people trust DNA tests even more because of the ability to use DNA to determine close family relations and even give an idea of past or distant family ties. Some comprehensive ancestry DNA testing services include building Family Trees and searching through Family History Records. This makes consumer DNA one of the best ways to uncover ethnicity and ancestry. 

Can saliva or mouth swab DNA tests be wrong

Yes, these can be wrong especially if the sample collection process has mishaps. DNA tests tend to be accurate when the procedure has been done meticulously. Precision is another reason why DNA tests are trusted. 

Can a health DNA test be wrong?

Can genetic testing be wrong?

Yes, Health DNA tests can be wrong. Like any other health tests, there might be a margin of error no matter how small. This at times is due to poor sample collection, a mistake during DNA processing or a mistake when comparing the DNA of different people within the databases. These are random occurrences that may lead to a false positive or false negative but these occurrences are very rare.  

How often are home DNA tests wrong?

Researchers conducted a study of 49 people who did a consumer DNA test. They conducted their own in-house DNA test and found out that only 60% of the results were similar. There is a 40% chance for it to be wrong if this study is to believe. However, most companies advise that their customers can do the DNA test twice for better and comparable results. 

Can a sibling DNA test be wrong?

Yes, even though sibling DNA testing is accurate. Inconclusive sibling DNA results are possible. Therefore it is better to obtain DNA from all 3 parties involved, namely the potential siblings and the known parent. 

Paternity DNA test accuracy

Can home paternity tests ever be wrong?

Yes, these kinds of tests can also be wrong for the same reasons as given above. To improve accuracy it is better to get DNA samples from all 2 (or more) parties involved, namely the potential siblings and the known parents. This prevents inconclusive DNA tests so a paternity test isn’t often wrong. It is also better to test again if there is doubt, and in the case that the test is of extreme significance to test using a legal testing service.

Prenatal paternity test can be wrong when not done at the right time. There are two kinds of these tests… the non-invasive prenatal paternity test from the mother’s blood, and the amniocentesis or chorionic villus sampling test (CVS). The latter method is invasive and may be a risk of generating complications.

Can ancestry DNA tests be wrong or inaccurate?

A genealogical DNA test is a DNA-based test that determines ancestral relationships by analyzing certain parts of a person’s DNA. However, different testing companies use different ethnic reference groups as well as different matching algorithms. These lead to ethnicity estimates for a person that vary between tests companies from simple differences to drastic changes. 

Could 23andme be wrong? Yes, in fact, all the DNA testing companies have shortcomings some are unique challenges and others plague the entire industry. For instance, each company has different reference databases and these are usually focused on European populations. So this can lead to mixed or wrong results.

Another problem is Inconsistencies between the different data sets. The results can be all over the map when you test with 2 or more companies. This is due to testing companies analyzing different alleles from different parts of the genome, as well as using different algorithms to process the data. In fact, AncestryDNA estimates of genetic ethnicity and it states that estimates are variable and depend on the method applied, the reference panel used, and the other customer samples included during estimation.” Therefore, DNA tests are probabilistic and not deterministic.

Other issues include variations. Ancestry tests look at SNPs on the gene but a gene has more than one allele or alternate forms of a gene that exist in the exact same place on a chromosome. So it might differ since you might have a gene for a trait such as red hair but not have red hair. Also, certain tests consider mitochondrial and Y chromosome DNA, while others don’t.

Privacy is a strong issue that plagues this industry. A lot of people are skeptical over what these companies use your personal information for. There is also the potential for information theft. For instance, MyHeritage had a breach of email addresses that may have affected the more than 92 million users. 

However, consumer DNA tests have built a strong reputation and if they are able to meet the challenges of the industry, they will have a foothold as one of the latest science-based industries in the 21st century.