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DNA testing for paternity - Online Doctor Chats

Date : 13-Jan-2012
User rating for this question
Very Good Posted in: General Health
Answered by

General & Family Physician
Practicing since : 2005
Answered : 2548 Questions
User :   I need some advice on paternity testing, result accuracy, and contamination.
Doctor :   Hi
User :   hi.
User :   I had a daughter last year on march 7th.
Doctor :  
please proceed with your query
Doctor :  
User :   There was 3 possible fathers.
Doctor :  
User :   in september i had a dna test done with one of the possible fathers.
Doctor :  
User :   He ordered the buccal swabs from a dna testing center somewhere, and they mailed them to his mom, and he drove here. he kept them in his car overnight. We took the buccal swabs outside by his car, we put them in the envelopes and shoved them in his backpack. I was wondering if there was anyway the results could have been contaminated
User :   Or if i should get a retest taken
User :   i believe he looks most like my daughter
User :   he also smokes, and may have been drinking alchol.
User :   if that makes any difference
Doctor :   ok

User :   They are saying i got pregnant june 8th, does that mean the day that the actual sex took place, or just when everything was implated and all.
Doctor :  
DNA testing for paternity is not affected by any of the contamination you have mentioned
User :   how is it affected
Doctor :   i am not clear with your question
User :   How is dna contaminated?
User :   I read that it is always good to get a second opinion is this correct.
Doctor :  
DNA contamination is again by genetics
Doctor :  
there is some thing called mosacism and chermism
Doctor :  
these things will give false results
User :   I read about that.
Doctor :  
well you are right it is good to take a second opinino
User :   But also it says that sometimes results can be contaminated if the test is not performed properly.
User :   Do you know anything about the due dates and things like that. I am just really trying to figure out who the father is, so i can get some closure.
Doctor :   not performed properly is MANUAL error
User :   what do you mean by manual?
Doctor :   it is a test right
User :   yes
Doctor :  
and it has to be done in a laboratory
Doctor :  
and it involves a set procedures
User :   Yeah. i get what your saying.
User :   If they say that they think I got pregnant june 8th,does that mean the 8th was the day of the actual sex?
Doctor :   it means that day fertilization took place between sperm and ovum
Doctor :  
it need not be the day of actual act
User :   how far behind can the actual act be?
User :   a few days?
Doctor :  
sperm can stay in the uterus for 3 to 5 days
User :   So i guess the best thing for me to do, would be to have all of the males involved tested.
Doctor :  
the best method to detect the paternity is DNA analysis
User :   what does that mean?
User :   Like which method?
User :   going to a testing center?
User :   What do you think about the tests in the drug store, are they totally bogus, or is there accuracy to them?
Doctor :   you have got the DNA testing done right for one of the person that method is the accurate method

Doctor :   test in the drug store??
User :   the buccal swabbing
User :   ??
User :   And there is a paternity test you can buy over the counter in the drug store.
Doctor :  
yes the buccal swab is the sample for the dna testing
User :   its somewhat like a pregnancy test type thing.
User :   Oh.
User :   ok.
Doctor :   over the counter test are not reliable
User :   okay.
User :   So there is no way that the tests could have been contaminated
User :   The dna still remained on the swabs for a few days.
Doctor :   DNA on the swab will remain for long time
Doctor :   it will be in months
User :   oh ok.
Doctor :   the samples collected for the dna testing will be buccal swab, blood, tissue cut from the forearm
Doctor :  
it is the buccal swab the most common as it is painless
Doctor :  
and the accuracy is 99%
User :   ok.
Doctor :  
as i said if the child is suffering from the genetic problem called mosacism or chemirism than there is chances of false results other wise it is not
User :   yeah but thats 1 out of a million
Doctor :   yes you are right

User :   I guess i am just indenial.
User :   i needed someone to confirm that the test results were accurate.
Doctor :   what did the test say?
User :   The tests results said there was a zero percent chance, and i was thinking even if there was a contamination, there would have been at least some percentage. my mom is always saying that it could be wrong because of the way we performed the test. I just always have it in the back of my mind.
Doctor :  
zero percent chance means that the tested sample is biologically not related to the child
User :   yeah.
Doctor :  
and he is no the father of the child
User :   i know.
User :   well thank you.
Doctor :  
is there anything else i can help you with?
User :   nope, unless you can perfom miracles, then i think i am good,
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