How Accurate Are DNA Tests For Paternity?

A DNA paternity test is carried out to determine if a man is the biological parent of a child. Often, they are conducted to settle disputes or for peace of mind. The testing process can be an emotional one for all involved so the accuracy of the results is of paramount importance. 

This post may contain affiliate links. I will earn a small commission, at no extra cost to you, if you make a purchase through an affiliate link.​

If you are awaiting the results of a DNA test, you may have concerns as to whether the results can sometimes be wrong. We have provided you with everything that you need to know about the accuracy of paternity DNA testing in our guide below.

How accurate are DNA tests for paternity

How Are DNA Tests Carried Out?

The earliest stage at which a paternity test can be carried out is 9 weeks gestation. This test is known as a prenatal paternity test.

The procedure is non-invasive and involves taking a blood sample from the mother and a blood sample or cheek swab from the potential father.

When the baby is born, the two most accurate tests involve taking a blood sample or a cheek swab. For a blood test, both the child and the potential father will need to visit a medical office to give a blood sample.

For a cheek swab, both the potential father and child will need to swab the inside of their cheeks to collect buccal cells. Some DNA tests will provide a swab for the mother too, however, in most cases, it is not a necessity for the mother to give a swab. 

How Accurate Are DNA Paternity Tests?

In the majority of cases, thanks to the advancements in technology, DNA tests are said to be 99.9% accurate as paternity fraud is relatively uncommon.

Depending on the company that you use, you will sometimes find that they conduct the test twice to confirm that the results are entirely accurate.

It is pretty difficult for lab results to be incorrect and although paternity fraud is uncommon in most instances, it is easier for the results to be manipulated or tampered with. 

Why Don’t Paternity Tests Show A 100% Paternity Probability?

As we have mentioned, most DNA tests deliver results that are 99.9% accurate. Now you may be wondering why they don’t show a 100% probability of paternity and this is because individuals that are not related can still share a considerable amount of DNA markers.

To get a probability of paternity as 100% all men of the same ethnicity would need to be tested. Of course, this isn’t going to be doable so the results are instead based on the statistics shared between the parties that are being tested.

If you receive a result that is 99.9% or over, you can rest assured that it is positive. 

How Accurate Are DNA Tests For Paternity?

How Can Paternity Tests Be Wrong?

There are several reasons as to why the results of a DNA test may be fraudulent and therefore irreflective of reality. We have identified a few potential issues below. 

A Lab Error May Have Occurred

In some instances, a lab error may affect the accuracy of the test results. For example, a human error may result in either a false positive or a false negative. If you receive your test results but have questions regarding the accuracy, it may be that a lab error has occurred. 

The Potential Fathers May Be Related

If there is a possibility that the potential fathers are related, there is a chance that the test results may be wrong. For example, if two brothers were involved in the situation, the test may say that one of them is the father even if they have not had any relationship with the mother.

Although this is not an issue that seems to occur often, it is still important to bear in mind if more than one individual is going to be sending a sample or a swab.

Moreover, if you have two alleged fathers in question that are related, it is recommended that both get tested along with the mother. This is going to increase the accuracy of the results. 

The Tests May Have Been Tampered With

In some rare cases, there is a risk that the DNA results may be tampered with. If you have carried out home testing and have sent the swabs off in the post, they may be swapped or tampered with to achieve either a positive or a negative result.

Although tampered test results are rare, it can happen if there is a dispute between the individuals involved. Also, if the man thought to be the father objects to this, he may use the DNA of another man in an attempt to alter the results. 

Can DNA Testing Facilities Tell The Difference Between A True Sample And A Fraudulent Sample?

There is no definitive answer to this question because there will be instances where they will be able to tell that the sample is fraudulent and others where they cannot. For example, they are likely to notice if a female’s DNA sample has been submitted instead of the sample of a male. 

Generally, at-home testing is not allowed for paternity disputes that are going through court proceedings. This is because, as we have mentioned, there is a chance that the tests may be tampered with or manipulated.

An independent witness that doesn’t have any involvement in the case, has to oversee the process to ensure that everything is done according to the rules. 

If you want reassurance or peace of mind, you may choose to get a home DNA test rather than go through the process of getting a legal paternity test. 

Final Thoughts

As you can see, it is pretty hard for DNA tests to be incorrect because you will usually receive an accurate result.

When the sample is being assessed in the lab, those responsible for determining the results are doing so from an objective standpoint so it is highly unlikely that they are going to try and tamper with the result.

Remember that if you are trying to settle a dispute a legal paternity test is recommended. 

Use these genealogy forms to stay organized as you discover your family history!

Get more of our favorite resources here!