What I Learned About the False Positive and How Was It Made?

One of the major labs that i'm using for this daily testing to get the n f el going and into their season, has made an error. The mistake when the samples come in, they're put under a hood, bi security hood, and the samples are transferred into a rack. And then the rack goes into the machine. So what was found was that the hood was contaminated. It was because the lab was mixing samples from non n f l sources and n f l sources  and putting em on the same rack. Once we knew that, next question is very simple, what are you going to do to assure that this never happens again? They answers were, we are not...