how long does it take for thc to not show up on a saliva swab text I took a saliva swab test for a drug screening for a new job today. I was offered the job and have been given my next month s schedule, but the test was done before this was given to me. I m assuming I passed, but would the saliva swab reveal otherwise if i just smoked marijuana yesterday or the day before ? I am a frequent smoker, at least 4-5/7 days a week..200 lb, 19 year old female.