How long does it take for results of a mouth swab tobacco test?

Depends on test: Many tests give instant results, but the strip may not be read instantly. Others are sent to labs where they are "developed, " and often positive screening tests are followed up by more definitive confirmatory tests, which can take many hours or even days to complete, depending on the kind of test and how many samples are ahead in the queue. If you are smoking, strongly consider quitting.