These test panels are cheap because there is really noting to them. They only look for the specified drug metabolites (sort of like a litmus test). The cut off for THC in a test panel is 50ng, so if this is the kind of test you will be subject to, then what ever the results you get will be the same as when you got for your test. However there is another kind of urine test they could do called GC/MS test and this one has a cut off of 15ng and looks at all aspects of your urine. In this case just because you pass a panel test does not guarantee a pass on a lab test.