A person is almost never informed that s/he had passed because s/he is presumed and expected to be clean. If youre waiting to be put to work, call the employer and ask for your "start date". The employers response would shed light on whether youve passed, or if the employer had moved on to the next candidate for hire. Never inquire about the test results. That just makes things look bad for you if you want to be viewed as a "clean person".

If you already have a start date secured, just simply show up for work and carry on with your duties in the manner that a "clean person" would. And again, dont discuss anything related to the drug test to anyone.