Paternity testing is used to establish the biological paternal parent of a child. The paternity testing, like any other test, is close to 100% accurate but not completely 100%.
There are, however, results that cannot be contested in a court of law due to the overwhelming nature of the results. There are two forms of paternity testing results - the exclusion and the inclusion.
The exclusion paternity test can be considered 100% accurate. The DNA from the baby is tested against the DNA of the father. The father is responsible for ½ of the chromosomes in the baby's DNA and thus the test will exclude a father than does not have any matching pairs of chromosomes with the baby.
The inclusion paternity test is a bit different. The results of the inclusion paternity test will tell how likely the father is to be the biological match with the baby. In most cases, the results will appear as a percentage. The best percentage is 99% and above.
The results of the paternity test are determined by the number of loci pulled from the donors. The best test results come from a paternity test using 16 loci. The loci are another name for DNA match points. Some paternity testing facilities will only test 13 loci. This test results will be less accurate than a test using 16 loci.
While DNA paternity testing has advanced to great heights over the years with most test results reaching as high as 99.99%, the acceptable percentage for paternity testing is 97% probability.