My serum and urine levels were ~80% of what they were this time last year when I was still smoking.
As a licensed competitive cyclist, just about everything you could put into your body ends-up tested for, even at non-nationals-levels, voluntarily by the teams themselves.
Even my caffeine levels get tested - and going over the allowed amount would kill me for sure - and that's from a person who believes she has too much blood in her caffeine-stream...
I vape more than I smoked, and there's still 20% less (not measuring bio-availability but simple volume present), so clearly in my case it's not _as much_ but "little to none"? I haven't had a cigarette in a couple months! How else would you explain how that nicotine got there, when it would have been nearly completely turned over in a week...