How to drug test for lsd. Flushing Internal dilution is accomplished by drinking great amounts of water in the time leading up to the urinalysis sampling. October 14, at The degree of migration and the color are characteristic of certain drugs. If the sample is positive, Barringer Technologies is knowingly urging parents to break the law. Despite what you might hear on the net, urinalysis, if done correctly, is a very accurate scientific procedure. I have been drug free for the last 5 months other than smoking synthetic weed and having to occasional beer. My husband tested positive on his last drug test, however, he was called back to work. Have you used one time per day?