Is it possible to cheat on a drug test?

If you really want to, you can cheat on any drug test. However, it is difficult to do, and skilled and experienced testers make it even more difficult. But it does happen, and the easiest tests to cheat on are scheduled drug tests. With random drug testing you never know when you will be called, so the only way to cheat on a random, unannounced drug test is to be prepared for one every single day.