All your questions about DNA testing, answered

DNA paternity testing (sometimes called parentage testing) uses DNA, the biological basis of inheritance, to prove or disprove the biological relationship between a child and an alleged father. It is because we inherit half of our DNA from our father and half from our mother.

In a DNA paternity test, DNA samples are taken from the mother, child, and alleged father and are sent to our lab. We purify the DNA and prepare it for testing to produce a genetic profile for each tested individual. The child’s profile is compared with the profiles of the mother and alleged father to determine whether he/she has inherited DNA from the alleged father. We then perform statistical analysis to calculate the probability of paternity.

DNA paternity testing is 100% accurate when done properly. Our Dual Process™ helps to ensure a strict chain of custody and error-free results through proper handling, testing, and analysis of samples.

Many laboratories mistake the term accuracy for likelihood (or probability). The Probability of Paternity is a statistical measure of the likelihood of the biological relationship. In the case of an inclusion result (the alleged father is found to be the biological father), the Probability of Paternity could be as high as 99.999% and higher.

All paternity tests will show a result below 100%—to produce a 100% probability, a laboratory would have to test every other man in the world. Instead, the paternity test uses a population database to calculate the probability of paternity. An exclusion result is always 0% because if the genetic profiles of the child and alleged father do not match, there is statistically no chance for the two to be biologically related.

No. Because DNA is set at conception and generally does not change, paternity tests can be performed even on a sample from an unborn child (called prenatal testing). At birth, blood from the umbilical cord can be taken for use as a DNA sample source, or a buccal swab may be collected from the newborn.

Testing through DNA Specialists of Houston follows a strict chain of custody, which allows our results to be defensible in courts and other government agencies. Many of our clients use our results to obtain child support and to claim Social Security benefits or inheritances.

For a chain of custody test, all test participants must bring a valid, government-issued ID such as a driver’s license, state ID, or passport. The child’s legal guardian must sign a consent form allowing the minor to be tested.

Chain of custody testing requires a custodian to sign the minor’s testing consent form. Verification of guardianship must be obtained at the time consent is given.

Yes. Buccal swab samples contain the same DNA as blood samples and will therefore produce the same paternity test result. Buccal swabs are especially preferable over blood samples for persons who have had recent blood transfusions or bone marrow transplants—their blood samples might contain DNA from the donor.

A paternity test result includes a table that lists the different DNA markers tested (the DNA profile), the Probability of Paternity, and a Combined Paternity Index (CPI) value. The DNA profile is the raw data on which the statistical calculations are based. You will want to focus on the Probability of Paternity. A result of 0% means that the alleged father is not the biological father; a result of 99.99% or higher means that the alleged father is the biological father. The CPI value represents the odds against another random, untested male in the population having the same results as the tested father.