The drug test is not done directly for the Suboxone or any other narcotic but it is done to know the metabolites of its major group. E.g. The Suboxone contains buprenorphine which is an opioid derivative. So they will test for the opioid metabolite. They have different cut off levels for its use. The test can show that either you are using as prescribed medicine or occasional use or as drug abuse. Because they have different cut off levels for these categories. For more details, visit drug test.