Gothen,

Yes, the test comes as positive or negative. Most labs have a cut of 50 mcg/unit. Supposedly, this is high enough that secondary smoke inhalation is not supposed to show positive. Smoked a few days prior to the test? Positive. Smoked a few weeks prior to the test, usually negative. However, THC likes to hang around in fat cells and is "supposedly" positive for a couple months.

Ed