What is paternity?
Paternity means fatherhood and is established when an accurate accepted paternity test is able to demonstrate that an alleged father is the biological father.
Paternity is excluded when the same methods and standards demonstrate that an alleged father is not the biological father.
How does DNA paternity testing work?
DNA analysis involves the direct examination of the genetic material that a child inherited from its biological parents. DNA is located throughout the human body and is identical in all cells. DNA in the blood is therefore the same as that in the skin, lungs, muscle, bone and various other tissues. An individual’s DNA is completely established at conception and never changes throughout life. Every individual’s DNA is unique except for identical twins. Since it is so specific, just like a fingerprint, DNA paternity is the most powerful form of testing.
During the paternity testing, the genetic characteristics of the child are first compared to those of its mother. Those characteristics in the child that cannot be found in the mother have been inherited from the biological father. If the tested man (alleged father) does not have the genetic characteristics necessary to be the biological father of the child, he is excluded. If the tested man’s DNA does contain those genetic characteristics, then the probability that this man is the biological father is calculated and reported by the laboratory. The tests performed by Unistel Medical Laboratories make use of DNA, usually obtained from blood.
How accurate is paternity testing?
The DNA patterns of the child, mother and alleged father are compared. If all the marker patterns match perfectly, the probability of paternity is greater than 99,999% – the alleged father is practically proven to be the biological father.
Where one or two marker patterns do not match AND these mismatches may be due to normal changes that may occur from generation to generation, a statistical chance of paternity is calculated that can be used in conjunction with all other evidence.
With three or more mismatches the alleged father is considered to be excluded – he is not the biological father.
What is the procedure to get a paternity test performed?
To perform a paternity test at DNA level a blood sample is required from the mother, alleged father and child. Children of any age can be tested. Unlike the traditional blood tests where the child had to be six months of age, there is no age limit with DNA. Paternity testing can be performed on unborn children. Prenatal paternity testing can be performed with amniotic fluid or a chorionic villus sample collected from the mother’s womb prior to birth or with fetal tissue. Paternity testing can also be performed using post-mortem specimens.
Can paternity testing be done without a blood sample from the mother?
Yes, it is possible to perform paternity testing by comparing DNA profiles from only the child and an alleged father when the mother is deceased. Legal guardianship is most important. However, it is strongly recommended that the mother be included in the testing. When all the marker patterns match, paternity can be considered VALID, not necessarily PROVEN.
Who must be present?
It is strongly recommended that all parties (mother, alleged father and child) be present at the same place, at the same time, unless circumstances absolutely prevent it.
If not possible, it is important to advise the laboratory of these cases. The samples are united once they all are received in the testing laboratory. The chain of custody must be ensured at all times. Samples collected early, can be stored as DNA for as long as necessary until all samples are united.
Kinship Analysis investigate the relationship between potentially related individuals.
In a case where the alleged parent(s) are not available for testing, a DNA profile Sibling Test can be performed to determine whether two individuals do in fact share the same biological parent(s). If available, it is recommended to test the mothers of the children, since half of their DNA is inherited from the mother and can be eliminated to compare the other half of the DNA against the alleged father. Statistical calculations are used to generate a percentage probability value. This value determines the most likely relationship between the individuals tested. The degree is given in the form of a likelihood ratio or odds (the greater the odds are in favor of one scenario, the more certain one can be that it is correct).
In a case where the alleged father is not available for testing, a DNA profile Grandparentage Testing can be performed to investigate the likelihood that they are the biological grandparents of the grandchild. It is recommended to test both grandparents in order to obtain the most conclusive results, since the child would have inherited DNA from the alleged father that also originates from the grandparent that was not tested.
In a case where the alleged father is not available for testing, a sibling of the alleged father can be tested against the child, using the DNA profile Uncle or Aunt Testing to investigate the likelihood that they are biologically related.
Y-chromosome Profile Testing
The Y-chromosome profiles are used to follow the paternal lineage, i.e. strictly male to male inheritance. All the sons of a man will have the same Y-chromosome profile. Full brothers, paternal half brothers, male children of brothers (paternal cousins), etc. will all have identical Y-chromosome profiles, indicating that they are from the same male lineage.
Twin Zygosity Testing
Twin zygosity testing is performed to determine if twins are identical (conceived from one fertilized egg which splits into two embryos early in development) or fraternal (conceived from two different eggs and sperm). Identical twins will have exactly the same DNA profile, whereas fraternal twins will have different DNA profiles, sharing only some of their DNA.
How long does it take to receive the results?
It generally takes 5-7 work days after receipt of the samples to receive the results for paternity testing and 5-15 work days for kinship analysis testing.
What samples are required?
A blood spot on a Guthrie card is preferred.
Alternatively 2 – 5ml blood in an EDTA tube (purple top) is required for each individual to be tested.
Prenatal paternity testing can also be performed on chorionic villus samples, amniotic fluid and cord blood.
What documentations are required?
The following procedures will be followed:
- Positive identification, such as an original identification document (Photostat to go with samples) or passport of both mother and alleged father. Drivers Licence or Asylum Seeker Permit are also acceptable.
- Birth certificate or clinic card of the child. When a guardian does not have a birth certificate or clinic card for a minor child, an affidavit has to be completed by the guardian and certified by a commissioner of oath. The affidavit must then be attached to the paternity documents. Contact Unistel for affidavit template.
- Consent from the legal guardian (to be signed on request form) to give permission for a blood sample to be taken from the child.
- The biological mother is to sign consent for blood sampling from herself and the child/children and verification that all samples were correctly labelled.
- All individuals under the age of 16 will be considered as minors, and requires signed consent by their legal guardian before they can be included in a paternity test.
- According to law, the biological mother is the legal guardian of a minor child. An alleged father is only considered a legal guardian if he provides a marriage certificate stating he is married to the biological mother or has a court order/divorce settlement granting him legal guardian status. In the case where another individual or family member is present to sign consent, as the child is in their care, he/she needs to provide a court order awarding them legal guardian status. If they are unable to do so, they have to be referred to the family court/family advocate.
- The alleged father is to sign consent for his blood sampling and verification that all samples were correctly labelled.
- If a paternity test is referred by the court, and the minor child’s name is stated in the referral, no consent from the legal guardian is required.
- All patients referred by the court need to provide a referral note/letter from the court – only then will the court referral rate be applicable. This result will then made available to the COURT and PATIENTS. These results cannot be withheld from the patients, as per the National Health Act. When the court pays for the test, results are ONLY made available to the court
- The mother and the alleged father will be required to certify that blood was drawn for the purpose of paternity testing and that the tubes containing the blood / guthrie cards were correctly labelled and identified.
- Payment for the test must be made up front by the party paying for the paternity test.
Pricing available on request from the laboratory.