5power

This forum is a life saver, been reading and learning alot.
I last smoke 18 days ago on March 6.
I smoke about 2 times a month or less. I am about 5'8 150 pounds. I snowboard twice a week and workout every now and than. Pretty fit.
I took a home test kit from CVS this past Friday with my first piss of the day and Pass it, was 11 days since I last smoke. I also took another one of a different brand on Monday and pass on the first piss. The line was pretty solid. Took another one today and was solid.
But I am still freaked out. The cut off for the home kit is 50 ng/ml, is there one lower that I can buy? What if my pre employment test is 15 ng/ml, what kind ot test cutoff do most employer look for? Because if it's a 15 ng/ml should I sub my urine or dilute? I really need some help in deciding what I should do. I take the real one on Friday but can delay until next week I think. I really need this. Thanks guys