after your blood has been saturated with thc it wont hold any more at which point you wont get any higher and the thc is deposited into your fat cells,since THC is fat soluble(sp?)it will remain there untill it has been fully flushed,minimul amounts of THC are being deposited into your fat cells while smokeing but unless you smoke far to much(like a blunt or 6-7 bowls or 2-3 joints)you will be clean in 1 and 1/2 too 2 weeks IF you dont smoke in those two weeks.so say you had one joint you will be clean in 10.5-14 days depending on your weight if you don't comsume any more weed in those days.
anymore questions feel free to ask and check out the erowid drug test page on cannabis(erowid.org)