well it's not only that but i've read different articles and they said even the even the best of labs they come back with erroneous samples and even if they get a a reading i guess they test the same sample again
Each sample is only tested once. 
mnli hypothesis: Each sample is only tested once.  premise: well it's not only that but i've read different articles and they said even the even the best of labs they come back with erroneous samples and even if they get a a reading i guess they test the same sample again