DNA Paternity Testing: How accurate are tests?

The most important question for anyone looking to have a paternity test is “How accurate is a paternity test?”

As with most tests nothing can ever be regarded as 100% but with developments in modern DNA Paternity Testing there is very little room for error. When taking a paternity test there are two main types of test one is an exclusion test the other is an inclusion test.

Exclusive paternity test results exclude a man from being a father of a child. This means that in the paternity test the DNA of the father did not sufficiently correspond to the DNA of the child to consider him as a prospective father. In this case the result should be 100% accurate, if a man is excluded from being a child's father there should be no way he could possibly be.

Inclusive paternity test results however are different, they refer to the likelihood that someone is the father of the child. Most inclusive paternity test results should prove at least 99%, preferably closer to 99.99% that a child is the father.

The accuracy of paternity test results depends on how many loci are tested on the DNA segments of the alleged father and child; the higher the number of loci, the greater the accuracy that can be obtained. For best results on a paternity test you should choose a forensic dna paternity laboratory test that tests at least 13-16 loci and that excludes fathers who show a difference in two or more DNA patterns on the loci.

To summarise although paternity test results can never be 100% through testing a larger number of loci (good DNA testing labs usually test about 16) a result should be 99.9% accurate. For more information on DNA Paternity Testing, Forensic DNA Paternity Analysis and DNA Paternity Expert Witness Services please contact Forensic Resources Ltd on 02920 647 043.