Marijuana use testing is becoming more and more commonplace in today's job market not just for health reasons but also for safety issues.  There is no formula to measure the length of time necessary for  person to rid their system of THC (the active ingredient in marijuana - delta-9-tetrahydrocannabinol). THC is responsible for the potency and effects of marijuana intoxication. Without this measurement formula, we have only guidelines and even they are rather arbitrary.

When testing for marijuana use, it is determined how clear the THC is in a person's system by the following factors: frequency of use of marijuana, duration of use of marijuana, amount of marijuana smoked and the potency of the marijuana. Clearance of THC in a person's system varies from ten to ninety days according to the usage of the previous listed factors.

There are five types of testing for detect marijuana use; a urine test, a hair test, a saliva test, a residue test and a perspiration test.

• Urine drug testing is the most popular methods of random testing as they are convenient and simple to use and provide fast, accurate results. However, the major advantage to urine drug testing is the ability to test up to ten different drugs at one time.

• Hair drug testing is currently one of the most trusted methods of drug detection. It is not only accurate but even the smallest amount of drugs will show up in hair from over a 90 day period.  It has consistently proven more effective than a urinalysis and other testing methods in correctly identifying marijuana users.  Hair analysis evaluates the amount of drug metabolites embedded inside the hair shaft by using a small sample of hair pulled or cut at the scalp.

• Saliva drug tests also provide fast and accurate results. Because this test can detect up to six drugs at one time, instantly, it is the preferred drug screening method at home and in the workplace. Saliva drug testing show marijuana use and the it's residues for up to three days.  It does not remain in oral fluids as long as they do in urine.  Most saliva drug testing kits provide a sponge which is used to rube the inside of the cheek to collect the sample of saliva.

• Residue tests or drug identification tests are effortless and easy methods of determining what drug is being used. Simple wipes can be used on a surface of a table, desk or an other surface where drug use is suspected. Law enforcement agencies and school officials now have the ability to test substances at the scene and obtain fast and laboratory accurate results.

• Perspiration tests are also approved for testing for marijuana use. There are studies that have shown the value of detecting drug use through sweat patch testing. But, the major drawback of sweat patch testing is that the production of liquid perspiration varies with room temperature and amount of physical activity. So, the volume of perspiration collected by the patch during the week that it is worn is unknown.

There is nothing a person can do to rid themselves of THC residue before testing for marijuana use.  There are no vitamin formulas or special teas nor does drinking lots of water help.  Best thing is to just stay away from it.