• "The laboratory you select must be accredited by the American Association of Blood Banks(AABB)... Under no circumstances should a third party be involved in the process of selecting a lab, scheduling the appointment, or any other process outlined in the next steps."

    U.S. Department of State
  • "Please be aware that many non-accredited businesses advertise on the Internet as being AABB-accredited. It is important to note that these "resellers" - who are not AABB-accredited - will claim to use an accredited lab for their testing. For the purpose of this request, samples collected from and comparative tests arranged through "resellers" will not be accepted. "

    USCIS - California Service Center
  • "The test must be performed directly through an AABB-accredited facility. Please visit the AABB website (ww.aabb.org) to find an accredited lab, which will also coordinate the testing of the claimed relative - if they reside overseas. Please be aware that many non-accredited businesses advertise on the Internet as being AABB-accredited. "

    USCIS - California Service Center
Home - DNA Basics - History of Paternity Testing
History of Paternity Testing

1800s – Paternity by Eye Colors

Throughout history, paternity was called into question when a child’s physical features were significantly different from his parents. Back in the 1800s, the paternity issue was occasionally brought up when a child’s eye color varied from the parents’.

At that time, it was generally understood that children received some of their physical features from their mother and some from their father. In 1865, Gregor Mendel, the Father of Genetics, developed formal scientific theories of genetic inheritance. He proposed that half of a child’s features came from the mother and half came from the father. This law became the foundation for all paternity testing from then on.

As research was done on the iris and genetics, scientists believed that the eye color was determined by the type of pigment in one’s iris. Since several genes contribute to the color of the iris, it is difficult to accurately predict the eye color of a child based on the eye colors of the parents. Therefore, it was never very useful to use eye colors to determine paternity.

1920s – Blood Typing

In the early 1900s, there was a scientific discovery about human blood types – A, AB, B, and O – based on the antigens found in the blood. This blood typing system was also called the ABO system.

In the 1920s, scientists found that blood types were genetically inherited. It was then possible to predict the child’s blood type based on the parents’ blood types or identify one parent’s blood type based on the child’s and the other parent’s blood types. The possible blood type relationships between parents and children are summarized in the following chart.

Based on this system, scientists used blood typing to determine paternity or maternity of a child. However, because of many variables in the blood relationships, it is difficult to conclusively prove biological relationships. As the chart indicates, the power of exclusion (the power of a test to eliminate a certain percentage of the population from being biologically related to another tested individual) in a blood typing paternity test is only 30%. Blood typing is not a useful technique for determining paternity.

1930s – Serological Testing

In the 1930s, scientists discovered the Rh, Kell, and Duffy blood group systems that could be used to identify humans. Like the ABO blood system, the new systems were based on the specific blood antigens genetically inherited from biological parents. Therefore, it was useful to identify possible blood relationships.

However, the serological tests based on the Rh, Kell, and Duffy blood group systems are not conclusive in identifying biological parents either. The power of exclusion in a serological paternity test is only 40%, not effective enough to establish conclusive biological relationships.

1970s – HLA Testing

In the mid 1970s, scientists discovered the human leukocyte antigen (HLA), a protein prevalent in all body cells except for the red blood cells. Because the genetically inherited HLA types between humans are highly variable, HLA testing became a more powerful tool to determine blood relationships. The power of exclusion using HLA testing alone is about 80%. When the testing is done with blood typing and serological testing, the power of exclusion is close to 90%.

However, because HLA testing requires a large quantity of freshly drawn blood sample, the collection process can be uncomfortable or even dangerous, especially for young children.

1980s – RFLP DNA Testing

After the DNA structure was discovered in 1953, a technique to test DNA was developed called restriction fragment length polymorphism (RFLP) in the mid 1980s. We all inherit our DNA equally from both parents and everyone’s DNA is different except for identical twins. Scientists discovered that there were highly differential regions on our DNA that could be used to identify each individual.

RFLP testing extracts DNA from blood samples and generates DNA profiles for all tested persons. The profiles are then compared to see if there is a match between parents and child(ren).

Because the DNA markers used in RFLP testing are highly differential, this procedure produces highly conclusive results with power of inclusion higher than 99% and exclusion of 100%.

1990s- Present – DNA testing using PCR

In the 1990s, polymerase chain reaction (PCR) technique became the standard process for DNA paternity testing. PCR technology allows scientists to amplify a very small quantity of DNA until billions of copies of the same DNA are made for testing and analysis. The PCR machine also makes this process happen fairly quickly.

Using PCR technology, DNA relationship tests can be performed much more easily and quickly. In a standard DNA paternity test today, buccal swab specimens are painlessly collected from each tested party in a non-invasive manner, making it ideal even for newborn babies. Because the quantity of DNA needed in the PCR based test is so small, genetic scientists can even test Amniotic fluid that contains the embryo’s DNA to determine paternity before the child is born.

Like the RLFP technique, the PCR based DNA relationship tests produce conclusive results to prove parentage with power of inclusion higher than 99% and exclusion of 100%.