Don't know why they would be contacting DOT. Usually the employer is the one they contact because they are the ones that paid for the test. I'm guessing its just being sent to GC/MS for confirmation which usually means the strip test came up with something. But strip tests pop false positives all the time for different substances so it may mean nothing. Nothing to do but wait for a couple more days and then maybe ask when you get to start at the new job. Never mention the drug test.