If you smoked today cigrette and you have a blood test tommrow?

Answer 1

If by "cigarette" you mean a marijuana cigarette -- and I assume you do -- your metabolism would need to be ridiculously high in order to burn it off before the test. You can try to claim that you attended a concert the night before, perhaps, accounting for its presence in your system. In the states, at least, most testing labs have raised the limit commensurate with a positive result because it's common place, particularly at concert venues and parties.