What is the Combined Paternity Index?
The Paternity Index is a number that represents the likelihood of Paternity. The number is calculated based on how common the genetic information found in your test result is within your race population. The Paternity Indices for each genetic locus tested are used to calculate a Combined Paternity Index which can result in a 99.999% Probability of Paternity, or even higher in the case of a true match. As an example, if the CPI is 9,999,987 it means the odds of the tested father being the unique biological father are 9,999,987 to one.
You will find a Combined Paternity Index in your DNA test report stated near the Probability of paternity. After DNA genetic testing is performed, each tested location that matches the other tested party is assigned a frequency, and the combined frequencies from all the genetic matches leads to a “combined paternity index” (CPI), such as 2,346,242. This means that the chance of another random individual matching your DNA pattern is 1 in 2,346,242. We can then use that calculation to arrive at a probability of paternity of 99.999957% (in this example).
