That’s an interesting question and one that’s probably been asked by college athletes and employees in various sectors more times than you could count. In the United States and in Canada, the most common means of testing for marijuana use is urine testing, and passing such a test is often a requirement for remaining on an athletic team or for gaining and keeping employment.
So what’s the answer? Well, it’s a definitive “It depends.”
The active ingredient in marijuana is THC. What a urine test actually looks for is the presence of THC-COOH, which is a metabolite of THC. It’s produced when the liver breaks down the THC in marijuana, and it remains in the body for a good deal longer.
The rate of THC metabolism varies from person to person. It’s also affected by how much marijuana has been used. Generally speaking, though, a first-time user or someone who only smokes from time to time will probably deliver a positive urine test for anywhere from a day to three days after use. By the end of four days, infrequent users will be below the level required to deliver a positive urine test, according to the NDCI (National Drug Court Institute).
Frequent users will likely test for about a week following their most recent use, but will in all likelihood show a negative at the ten-day point. That said, there’s really no guarantee that a heavy user will be free from THC metabolites within ten days – some users even test positive a month after they’ve last used. And in one (admittedly extreme) case, a user-tested positive on the 67th day following his last use.
Is It Possible to Fool a Urine Test?
Again, athletes and employees have reason to be concerned. Marijuana is one of the most common drugs tested for, and it can get a user into just as much trouble as hard drugs when it comes to being kicked off the team or losing a job.
Drinking a lot of water to dilute the THC metabolites in the urine is the most scientifically sound solution – water dilutes EVERYTHING in the urine. But the chances of a person being able to actually consume enough water to achieve a negative result if he or she has been smoking marijuana are slim to none. Besides, urine that’s too diluted is immediately going to be flagged as having been tampered with.
As to the products that are available on the Internet that purport to “clean” the urine, you users might just as well tear up their money and flush it down the toilet along with any tainted urine they’re trying to get rid of. Simply stated, they don’t work.
And if the drug test is DOT mandated, forget it. DOT urine specimen collectors are highly trained. They’ve completed courses that qualify them in collection techniques that are essentially foolproof. Substituting someone else’s urine or otherwise tampering with the specimen is simply not going to be possible., and they never leave a subject alone for even a second, so substituting someone else’s urine isn’t possible.
The Final Word
People who don’t want to test positive for marijuana use would be well advised to simply leave the weed alone. The length of time that it can remain in the system is entirely too variable, and the test is reliable. The only truly reliable way to prevent a positive result is to not use it.