Hi..
According to the American Lung Association "nicotine disappears from your blood stream and your urine within 72 hours after smoking your last cigarette."
However, the metabolite of nicotine which is known as Cotinine leaves its traces in blood as well as in urine for up to 7 days ( sometimes up to 3 weeks).
About 85 to 90 per cent of the nicotine which is present in your blood is metabolized by the liver and is thrown out of your system
by the kidney. But due to the higher concentration, many a times, it still persists in the blood stream.
to be on the safe side try to stop smoking or being around smokers 1 month before the Test
Note: per your request I'll not advice you to quit smoking (still it's your Doctor responsibility)
Good luck
