Blood Drug Testing

How long can you tell by a urine test that someone smokes or used to smokes cigarettes?

How long after your last cigarette will your urine test negative for nicotine or cotinine? My research came up with times between 2 days to 3 months. Can anyone narrow that down for me???? Much thanks

Public Comments

1. It depends on the sensitivity of the test (along with a number of other variables). Cotinine has a half-life of about a day, so assuming no additional exposure then your urine will contain half as much cotinine for every day that goes by. A couple of things to watch out for, if you are using nicotine replacement (i.e. patches or gum) then the nicotine (and hence the cotinine that the liver breaks it down into) from them is indistinguishable from the nicotine and cotinine from the cigarettes that you haven't been smoking. Also, nicotine isn't just found in tobacco, probably best to avoid eating eggplant, tomatoes and potatoes as well, if you want to get your cotinine levels right down