On the other hand,
studies have shown that regular users can test positive (20 ng/ml limit) for THC metabolites for up to 46 consecutive days following marijuana usage. In an
extreme case, a heavy cannabis user of more than 10 years was able to test positive (20 ng/ml limit) for up to 67 days after last being exposed to marijuana.
How Long Will I Test Positive For?
Based on these findings, it is impossible to say for sure how long marijuana will remain in your system for. There are a number of factors that contribute to this uncertainty, such as the level of THC dose, method of intake, duration and frequency of use and your body’s metabolism rate. On top of all that, various drug tests have different levels of accuracy and cut-off limits.
As studies have shown, the chances of testing positive for marijuana – even after a break in use – are much higher if you happen to be a regular user as opposed to someone who has just smoked once or twice in the past few weeks.