Grandparent DNA Test

A grandparent DNA test is just as accurate as a paternity test, but the conclusiveness of the results can have more variation. For example, the probability of a relationship between a father and child is almost always 99.9% or higher – or 0%, but for a single-grandparent test, the probability of a relationship might be 92%, which is still considered a conclusive result.

To strengthen the conclusiveness of test results, we recommend that both paternal grandparents test (if possible) and the child’s mother participate in testing. When both paternal grandparents and the mother participate in testing, probability of paternity is nearly always 99.9% or higher.

Yes, a grandparent DNA test can be used for legal reasons as long as a chain-of-custody procedure has been set up and followed. Results from a legal grandparent DNA test are court-admissible and can be used for legal reasons such as Social Security, inheritance rights, custody, and more. Results for an at-home grandparent DNA test cannot be used in court.

The probability of relationship (PRI) is given as a percentage in your grandparent DNA test results report. You can interpret your results based on the following:

• 90% or higher: the relationship is supported by DNA testing
• 9% – 89%: inconclusive result, and additional parties need to be tested
• Below 9%: the relationship is not supported by DNA testing

If a probability of relationship (PRI) of 93% is given for a grandparent test, the result could be understood as: “There is a 93% probability that the persons tested share a grandparent/grandchild relationship.”