Paternity test 97.999, is it biological?

Paternity test results show that there is usually a 97.999% probability that the child can be identified as biologically related. Paternity testing calculates the paternity index by comparing DNA sites. When the probability exceeds 99.99%, the biological paternity relationship can be confirmed. The result of 97.999% indicates that there is a strong correlation, but it needs to be comprehensively judged based on the specific number of detection sites and laboratory standards.

At present, mainstream paternity testing uses more than 21 STR loci for testing. If the test result reaches 97.999%, it means that the tested man and the child share a large number of genetic markers. This value means that in a random population, the probability that another individual will be the biological father is extremely low. Laboratories usually describe this result as "most likely to have a biological parent-child relationship." In actual cases, such data are often due to insufficient detection sites or special gene mutations, resulting in values ​​that do not reach 99.99%.

When a critical value such as 97.999% occurs, there may be test sample contamination, genetic mutation or rare inheritance pattern. Some laboratories will recommend additional testing for Y chromosome or X chromosome specific markers, or increase the number of testing sites to more than 40 to improve accuracy. In consanguineous families, relatives such as uncles and nephews may share similar gene segments, which will also affect the final probability value calculation.

It is recommended to choose an identification institution with judicial qualifications for re-examination and re-collect standard samples such as oral mucosal cells to eliminate the possibility of sample confusion. At the same time, the laboratory can be required to provide complete detection site data and mutation analysis reports, and if necessary, triplet testing can be performed with the participation of parents and children. In daily life, you should pay attention to keeping the original appraisal report to avoid creases or contamination that will affect subsequent use.