DNA tests are often reliable for determining paternity, ancestry, or solving crimes. However, one of the most common questions people ask is; can a home DNA test be wrong? Of course, like any other tests, DNA tests are not infallible and can potentially produce wrong or inaccurate results.

Since the last thing you probably want is for your home DNA test kit to be wrong, we will explore the common factors that can cause inaccurate results. Let’s jump right in, shall we?

Factors That Could Cause Incorrect DNA Test Results

Human Error

According to Forensic Science International, human error is one of the most common causes of inconclusive DNA test results. Mistakes such as sample mix-ups in the laboratory or improper collection of DNA samples can cause wrong DNA test results. Additionally, mislabeling of samples and misinterpretation of results by laboratory technicians can also contribute to incorrect findings.

Similarly, there are cases where people deliberately substitute DNA test samples in a home kit which could cause incorrect DNA results.


Contamination of DNA samples is another common factor that can cause inconclusive results. This often happens when DNA samples are mixed up with DNA from other sources. For instance, if you cough or sneeze while handling your home DNA test kit, you could contaminate the sample and cause erroneous results.

Besides that, contamination can also happen when someone else touches their nose, mouth, or face and then touches the DNA sample. This is because they’re introducing new DNA which can compromise the DNA test results.

However, when you’re using a home DNA test kit, you can minimize contamination by wearing a mask and gloves when collecting the samples.

Twin-Related Test Candidates

Did you know that identical twins share almost the same exact DNA? This means that it’s possible for paternity test results to be misleading if closely related siblings are involved, especially if they’re identical twins. However, non-identical siblings share at least 50% of DNA which is enough to trace down the origin of the subject.

DNA Mutations

Even though DNA mutations are rare, they could cause incorrect paternity test results. This often happens when a sperm cell contains a mutated gene that alters the child’s DNA makeup and causes it to differ from that of the father. However, DNA mutations in sperm are more common in older men compared to younger individuals.

Beyond that, people with chimerism could have inconclusive DNA test results. This is because people with chimerism have two different sets of DNA in their bodies.

Technical Limitation of DNA Sample

In some cases, a DNA result could be inconclusive if the test sample was limited. For instance, DNA tests using hair samples are less accurate with an average success rate of 60%. However, DNA tests conducted using blood or cheek swabs have a success rate of almost 100%.

The DNA sample could also be limited by the environment — heat, sunlight, water, and oxygen can affect the usefulness of a DNA sample.

Take Extra Precaution When Handling a Home DNA Test Kit

Although factors such as DNA mutations and identical test subjects can cause an inconclusive DNA test result, human error, contamination, and technical limitations are some of the most common culprits. Because of that, we recommend you take extra precautions when handling your home DNA test kit by following all the instructions on the package.

However, if you’re not certain about the results, you can consult us to help you figure it out.