What would cause an inconclusive paternity test result?
Amber Shaw, of IDENTIGENE’s customer service answer’s this weeks Ask Kate question.
Inconclusive paternity test results generated by most laboratories typically means that the probability of paternity was < 99%. This is most likely caused by a number of differences between child and the alleged father at one or more genetic markers (loci) or the alleles (genetic variations) shared between child and the alleged father were so common that the collective strength of all the markers did not add enough statistical strength to the calculation to give a definitive “not excluded” result.
Differences between child and the alleged father could be caused by true generational mutations which occur naturally and randomly thru generations. Because the mutations are taken into consideration in the paternity calculations, the probability suffers because the dissimilarities between child and alleged father must be accounted for.
The results calculation is based upon the individual relationship indices (RI). The RI indicates how common, or how rare, each marker is at each locus according to population. If you have one (or more) rare markers that are passed to the child, that index number will increase the combined paternity index (CPI). An inclusive result is a combined parentage index of 99% or higher.
IDENTIGENE releases definitive results based upon two things:
- Inclusions: Probability of paternity of 99% or higher.
- Exclusions: 3 or more exclusionary markers (alleles do not match between child and the alleged father).
Many laboratories release an exclusion result requiring only 2 exclusionary markers be present. Our minimum is a more conservative number of 3 exclusionary markers. Although it is less likely to have 2 differences between a child and true biological father, it is still possible and based upon what is seen in the laboratory, implies there needs to be more investigation because a close relative of the alleged father (such as the father or brother of the alleged father) could potentially be the father . IDENTIGENE releases a result of inconclusive when there are 2 differences between child and an alleged father for two reasons:
- Because exclusionary results are definitive, we take a more cautious and conservative approach to ensure the result is as accurate as possible.
- Typically when two differences exist between child and the alleged father, the brother of the alleged father is a potential candidate for being the true biological father. This is based upon experience on what is actually seen in the laboratory and deserves closer examination.
Read here for more information on understanding the Paternity Index: http://www.dnatesting.com/dna-testing/paternity-index.php
If my results are inconclusive, will identigene request I send a sample from the mother? Or will I have to pay for a whole new test? Getting a sample from the mother is going to be an issue so I’d like to avoid it if it’s not necessary.
It’s not required that you include the mother in the test, how ever it does help. Once Identigene receives your samples, if the lab needs the mother’s samples to give a definitive result, we will call you and request her samples. At that point, you will have the choice of sending her samples, or continuing the test with out them, knowing that you MAY get an inconclusive result.
One reason we request the mother’s samples up front is that it will prevent the delay in reporting, while we contact you, wait for the samples, and then continue the test.
how long can yoy keep the sample
Evelyn,
Once you collect the samples we advise to send them in as fast as possible; however, if you do need time we advise within 6 months of collection.
If a test is inconclusive, could the reason be because the person tested is related to the father?
Not necessarily. If there is a possibility that the alleged father being tested could be a relative of some kind you do want to notify the laboratory of that possibility before testing. In order to get a conclusive answer different calculations need to be done.
a result of 93.7 was found but I don’t know if it’s positive my report didnt say inconclusive tho. any advise?
by the way it wasnt from your company
Hello Jess,
Most laboratories will not report anything as conclusive if its under 99%. I would recommend contacting the laboratory that completed the test and having them explain the percentage of probability of paternity.
My Dna says 99.73% it says I cannot be exluded as Biologoical father of child
is it ok
HI Paul,
Anything above 99% is considered to be a not excluded, meaning we do consider you to be the biological father of the child. If you would like to know more about your results please feel free to contact our client support team Mon-Fri 9am-8pm EST and they are more than happy to go over what each section means.