Your confidential paternity test results will be emailed to you within 3–5 days after we receive your DNA samples in our lab. In the DNA paternity profiling test report, a conclusion will provide one of two statements:
- This result provides (extremely/moderately) strong support in favor of paternity, or
- This result excludes the alleged father as the biological father.
These conclusions are reached after our in-house geneticists have examined up to 35 short tandem repeat (STR) markers in the DNA profiles of the sample donors (the child, the alleged father and sometimes the mother). Each individual has two copies of each STR marker, known as alleles: one is inherited from the father and the other from the mother. These alleles at each STR marker are compared between the donors. There will need to be a match with all STR markers tested for an inclusion of paternity.
Calculations used in paternity test results
The paternity index (PI) is a statistical calculation that compares the DNA profiles obtained to an untested random individual within the general population. In other words, it is a way of measuring the strength of a particular match based on the relative uniqueness of the allele observed. For example, if most people have the same allele at a particular location, the PI might be lower. If two tested individuals match at an allele, it could indeed be because of a parent–child relationship, but it could also be because most people match with this allele at this location. On the other hand, if very few people have an allele at this location it’s rarer and the PI value would thus increase.
The combined paternity index (CPI) is a calculation based on the product of all paternity indices that helps formulate the probability of paternity. If the CPI is greater than 1000, there is a match between the alleged father and child. Therefore, a CPI value greater than 1000 means that the probability of paternity is over 99%. If the CPI is zero, it is a non-match between the alleged father and child. This means that the alleged father is excluded as being the biological father of the child.
The probability of paternity indicates the chance of paternity. In other words, it is the statistical probability of the alleged father being the child’s biological father and not any other man from the same ethnic group who may share a similar DNA profile by random chance. If the probability of paternity is 99.99%, for example, this means that the alleged father is 99.99% more likely to be the biological father of the child than another man chosen at random from the same ethnic group.
More information on paternity test results can be found in our Learning Center articles Paternity Testing FAQs and DNA Testing FAQs. If you have any queries or need further information on any of our DNA testing services, please contact AlphaBiolabs via Live Chat or call now at 727-325-2902.