What is paternity/parentage testing?Paternity/parentage testing encompasses the laboratory determination of the parentage of a child.
Who may require a parentage test?
- Any person who wishes to prove or disprove that they are the biological parent of a child.
- A mother who wishes to prove that a certain man is the biological father of her child or children.
- A man that is already paying maintenance for a child but has doubts about his alleged paternal status.
- The parents of babies that may have been mixed-up soon after birth.
- The relatives of a deceased man when there is a claim against the estate by a woman claiming that the deceased man is the father of her child.
- Individuals wishing to immigrate to certain countries where one or both of their parents are living.
- Individuals that were adopted and who are trying to trace their biological parents.
Kinship testingA DNA kinship test will test the relationship between two or more individuals to assess an alleged relationship such as full or half siblings, grandparents and aunts or uncles.
How is parentage testing usually done?
- A source of DNA (usually a sample of blood) is obtained from the alleged parent/s of the child as well as the child.
- DNA is isolated from the sample.
- The DNA base sequence variants present at a number of fixed locations in the DNA are then identified.
- An attempt is made to trace each of the child's identified variants back to the alleged parent/s. Each variant in a child should have a counterpart in at least one of its biological parents.
- If the child is found to possess two variants at a particular location that are not present in an alleged parent, then the alleged parent is unlikely to be the child's biological parent. The word 'unlikely' is used because very rarely DNA alterations (mutations) take place during sperm or egg formation that may result in inconsistencies of this sort. Generally, the presence of two or more inconsistencies must be observed before an alleged parent can be excluded with certainty.
- When the variants present at several (usually 15) locations in the DNA can be traced back to the alleged parents it is highly likely that the alleged parents are the child's biological parents.
AccuracyIn cases where a mother, her child and an alleged father are tested and no inconsistencies are found, the probability of paternity is generally greater than 99.9%. In cases where two or more inconsistencies are found, the probability of paternity is generally less than 0.01%.
We confirm every test result obtained by repeating the DNA test on the samples from the child and alleged father/mother.
ResultsResults are routinely sent by registered mail to the person (usually a maintenance officer at a magistrate's court, a doctor or a lawyer) that referred the parties for testing. Each individual is also entitled to his or her own copy of the report.
ProcedureA referring letter is required from a magistrate's court, a doctor or a lawyer. On receipt of a deposit (half the total sum) an appointment date will be scheduled by the Outpatients Department of the Braamfontein branch of the NHLS. The balance is to be paid on the day of the appointment. The results will be forwarded to the referrer by registered mail.
RequirementsIndividuals should be in possession of an identification document and a recent photograph. There is no age restriction and the test can even be done before the baby is born (by special arrangement). If any of the parties have had a blood transfusion within three months of the appointment, they must declare this so that blood is not used as the source of DNA. In the majority of cases where there is a mother, one or more children and an alleged father, all individuals are required to be present at the same time in one room when samples are taken.
Protecting the childThe importance of protecting the child emotionally is recognised. For example, where the child knows the alleged father as a friend but not as a prospective parent, separate appointments at different times of the day will be scheduled, e.g. a morning appointment for the alleged father and an afternoon appointment for the mother and child.
Contact informationFor further information, or to schedule an appointment, contact the Outpatients Department of the NHLS on
Gauteng Region-Braamfontein LaboratoryTel: +27(11) 489-9470
Free State-Universitas HospitalTel: +27(51) 405 3283
Tel: +27(51) 405 3887
KwaZulu-Natal-Addington LaboratoryTel: +27(31)327 2463/2479; +27(31) 337 0462
Western Cape - Groote Schuur Hospital
Tel: +27(21) 404 3091
Parentage testing by the NHLSAccurate determination of parenthood can be extremely important for the material and mental well-being of a child and its real and possible parents. Fortunately paternity (and maternity) testing has become a very accurate science and one with which the National Health Laboratory Service's Department of Human Genetics has been involved for more than 20 years.
Most cases are resolved by typing DNA prepared from small volumes of blood or buccal swabs. We currently use 15 Short Tandem Repeat (STR) DNA polymorphic markers to determine paternity or maternity.
We confirm every test result obtained by repeating the DNA test on the samples from the child and the alleged parent. Furthermore, Y-STR markers are available for additional confirmation of paternity test results when the child is a male (at an additional cost).
Y-chromosome specific STRs are also important tools in paternity cases involving a deceased alleged father. In such cases, it is possible to obtain evidence of paternity by typing the Y-chromosome specific STRs of the alleged father's male relative.
Doctors, attorneys or maintenance officers usually refer parties requiring parentage testing. Individuals are properly identified before samples are taken and these are hand delivered to the laboratory. On completion of the tests, a written report is sent by registered mail (and faxed if necessary) to the referrer. The names of individuals, who have been tested, as well as the results of the tests, are strictly confidential.
Paternity testing can be performed without a sample from the child's mother but it is more accurate when one is available.
The time required for completion of the test is roughly 10 working days.
Kinship testing is also done by the NHLS.
For more information, telephone +27(11) 489 9470 or fax+27(11) 489 9635.