Recent events have aroused interest in paternity testing, both in show business and politics. Rumors will only be just that, rumors, unless the interested parties can prove their claims with paternity testing. The more comprehensive term is relationship testing, since we can also test for different relationships, like siblingship. Or let’s say the putative father is no longer available for testing, either due to death, inability or refusal of the alleged father to be tested.

Relationship testing is resorted to prove or disprove paternity for different reasons. Most common reason to test is to prove that a man is the father of the child/children, either for inheritance purposes, child support, rape and immigration. There are not many cases for testing, due to the expense involved in DNA testing, which is the most accurate technique available today.

Based on medical literature, about a fourth of the cases tested are exclusions, meaning the tested man is not the biological father of the child. As we jokingly say, only the women are sure that the child is theirs, and men will have to prove their paternity the hard way.

DNA testing is a high complexity test, with heavy emphasis on the chain of custody and to document the identity of the parties tested. It is a must, especially for legal and immigration cases. A paternity test done without a chain of custody is practically useless in court. The process involves many steps, which must also be documented for traceability, and if the initial testing shows an exclusion, it must be repeated with a different sample from all parties to ensure accuracy and eliminate the possibility of specimen switching. We practice the most stringent measures in the entire laboratory with paternity testing.

In cases where the alleged father is dead, an exhumation can be done to retrieve DNA from the body. Obviously, cremated remains or ashes are not acceptable for testing. For families who anticipate paternity claims of their deceased male relative, it is best to ask the laboratory to obtain samples from the deceased’s body before burial or cremation and get a DNA profile which can be compared later on with any claimant for inheritance.

When the family is averse to exhumation or the body had been cremated, we can still perform relationship testing if enough close relatives of the deceased are available to test from which we can infer the deceased’s DNA contribution, if any, to the child/children.

For example, the deceased man is no longer available for testing, we will need DNA samples from the child, the biological mother and acknowledged children of the alleged father. The more siblings we test, the more definitive the results will be. If the alleged father’s parents and siblings are available for testing, the scenario is easier to deal with in terms of ascertaining the alleged father’s DNA profile, and thus, make a definitive statement of paternity/non-paternity.

Legally speaking, a Probability of Paternity (POP) of 99.5 percent is required. Anything less is not conclusive and more DNA markers are necessary to increase the POP. For most cases, a set of 15 DNA markers is sufficient to get a minimum 99.5 percent probability of paternity.

Fortunately, the Supreme Court has issued a set of instructions about paternity testing. Most judges now know more about paternity testing than before. However, I am usually required to render expert testimony before the judge accepts the results, which is actually more instructive for judges and expands their knowledge of the subject matter.

The Association for Advancement of Blood and Biotherapies (AABB), formerly known as the American Association of Blood Banks, is the only entity that performs accreditation of relationship testing laboratories worldwide. The accreditation process is very comprehensive and rigorous in its requirements to qualify for accreditation. It examines every facet of the relationship testing process and an accredited laboratory has to be evaluated every two years to maintain its accreditation.

The St. Lukes Medical Center Relationship Testing Laboratory was first and only AABB-accredited in 2014 and has maintained its status as the only Philippine laboratory to be so accredited up to the present through the re-accreditation process. It was also the first relationship testing laboratory outside North America to be AABB-accredited. As such, we cater to the relationship testing needs of the American embassy and other embassies of other countries.

To date, we have performed over 10,000 DNA profiles and as its director, I have testified as an expert witness in over a hundred cases in the local courts, all of which have been accepted as valid by the judges hearing these cases.

Relationship testing is an indispensable tool for the legal system, removing doubts and establishing definitive answers in court cases, be they civil or criminal in nature. It answers the question: “Who’s Your Daddy?”