It's not only a fault with the individuals in terms of using the actual result. It's a fault in operating the machine.
I've been in a visit room where you queue up and one person after another goes in. People who don't know one another and who have never met before but are in a queue to go in to visit will all hit positive for a combination of the same three drugs. What does that say? It says the machine is not being cleaned.
It's about the operating problems, setting the machine, cleaning the machine, the real attention to it, and then the procedure afterwards. If you do hit positive, there has to be some way to verify what that positive hit means and whether it's false or not, and there isn't a procedure.