Understanding DNA Test Results - Report


After collected specimens are analyzed at the laboratory, DNA is isolated and amplified for detailed examination. All 16-loci examined for each test participant will be further interpreted by our staff scientists to confirm the validity of the hypothesized familial relationship. As provided in the DNA paternity testing examples below, each participant's genetic information will be documented to allow for ease of evaluation at each DNA locus.

Paternity Test and Motherless Paternity Test

In performing a detailed review of the data shown on a DNA paternity test report, each locus of the child can be compared to that of the biological mother to determine the mother's contribution. For example, even if both the alleged father and child possess an "11" at locus "XXX", this would still be considered a genetic mismatch due to the fact that a locus within the child's profile must first match with one in the mother's.

In the event that the mother is not available for testing, a direct comparison between the alleged father and child can be performed.

Paternity Inclusion and Exclusion

The terminology used in reporting DNA paternity test results is a paternity inclusion versus a paternity exclusion. If all chromosomes within each locus tested demonstrate an appropriate genetic match between the alleged father and child, then a paternity inclusion can be determined, proving that the alleged father is the true biological father. Alternatively, the alleged father would be eliminated from being biologically related to the child whenever there are at least two non-matching loci, and this is reported as a paternity exclusion.

Combined Paternity Index (CPI)

A probability of paternity, normally >99.9% or 0% depending on the test results, is generated with statistical calculations performed based on the Combined Paternity Index (CPI). The CPI is the outcome of multiplying the Paternity Index (PI) produced at each locus. If there is a match between the profiles of the alleged father and child, then the PI is calculated. The PI will have a value of 0 whenever there is a non-match between the two. In conclusion, the CPI will be 0 if a paternity exclusion is found, resulting in a 0% probability of paternity. Likewise, if the CPI is greater than 1000, a paternity inclusion can be confirmed with the probability of paternity at >99.9%. The results of the DNA paternity test are absolutely conclusive and will state conclusively whether the tested man is the true biological father of the child.

Next: Example of Exclusion »