All drug testing is monitored as it is a leagal chain of custody. Each employer pays for their own testing, results are not shared. Each request for a test even if it's the same person being tested by 10 different companies is considered a separate request so you would have to make 10 appts and submit 10 different samples.

If a test is screened as positive No further quantitative testing is performed unless requested by employer. I used to be a med tech. I don't know the specifics about the new technology that can tell if the specimen is diluted. I only know that I saw it for the first time just the other day. A real easy way to find out is to call the local hosp and ask for the lab. Ask them. They should be able to tell you everything about it even if they don't use that particular methodology. They will probably tell you what won't work to beat it.