• "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 - DNA Test Applications - DNA Family Relationship Testing
DNA Family Relationship Testing

Using PCR technology, DNA analysis is widely used to determine genetic family relationships such as paternity, maternity, siblingship, and other kinships.

An individual’s DNA compliment is formed during conception when the father’s sperm cell and the mother’s egg cell fuse to form a fertilized egg, called a zygote. The zygote contains a complete set of DNA molecules. This is a unique combination of DNA equally inherited from both parents.

Once an individual’s DNA makeup is formed at conception, it does not change. Since the DNA in the zygote multiplies and develops into a human being, all the cells forming the body contain the same DNA—half from the father and half from the mother. This fact allows the relationship testing to use all types of DNA samples including loose cells from the cheeks collected using buccal swabs, blood, or other types of body liquid and tissue samples.

A small portion of the DNA contains coding information for physical features and functions. There is some non-coding genetic material called junk DNA, which genetic scientists found is useful for individual identification. There are some special markers on the junk DNA, which are highly differential among individuals. Since half of our DNA comes from the father and half from the mother, there is a match of these special markers between parents and children.

The combination of these selected markers found in each person makes up his or her unique genetic profile. When determining the relationship between two individuals, their genetic profiles are compared to see if they share the same inheritance patterns on the selected markers at a statistically conclusive rate.

For example, the following sample report shows how relatedness between parents and child is identified on some of these markers:

DNA Marker Mother Child Alleged Father
D21S11 28, 30 28, 31 29, 31
D7S820 9, 10 10, 11 11, 12
TH01 14, 15 14, 16 15, 16
D13S317 7, 8 7, 9 8, 9
D19S433 14, 16.2 14, 15 15, 17

The partial results indicate that the child and the alleged father’s DNA match among these five markers. The complete paternity test results show this correlation on at least 13 core markers between the child and the tested man and draw a conclusion of whether or not the man is the biological father.

Scientifically, each marker is assigned with a Paternity Index (PI), which is a statistical measure of how powerfully a match at a particular marker indicates paternity. The PI of each marker is multiplied with each other to generate the Combined Paternity Index (CPI), which indicates the overall probability of an individual being the biological father of the tested child relative to any random man from the entire population of the same race. The CPI is then converted into a Probability of Paternity showing the degree of relatedness between the alleged father and child. Typically, a DNA paternity test produces results that confirm paternity with a probability higher than 99% or disprove the relationship with an exclusion of 100%.

The testing methodology for other kinship tests such as grandparentage and siblingship tests is the same. People related by a close blood relationship share many common DNA markers, which are manifested in their genetic profiles. If there are shared markers among these individuals’ profiles, the probability of relatedness can be calculated using the kinship index systems. Like the probability of paternity, the reported probability of relatedness will indicate the likelihood of the tested parties’ blood relationship.

DNA Test Applications