Marijuana (cannabis) is included in most standard and expanded drug tests. A urine, blood, saliva and hair sample test can all detect marijuana use. This is true whether or not it was used only once or is used chronically.

Marijuana can show up in the urine if used one time, for a period of 1 to 6 days following the exposure. If a person uses marijuana on a weekly basis, it can be detected up to nine days after the last use.  Those who smoke marijuana every day will find that a drug tests will be able to detect use for 7 to 30 days after they last smoked it. All of these figures are for urine tests.

Cannabis can also be detected via hair, saliva and blood tests. When a hair test is taken the period of detection is 90 days or roughly three months.  A blood test will be able to detect cannabis for two to three days after a person has used it if they only use it occasionally. Persons they use it often will find that it can be detected in the blood for about two weeks.

A drug test will look for the presence of THC. If none is found, the person will pass. It is possible to get a false positive. Common substances or medications which can cause a false positive for a cannabis test include riboflavin, which may be taken in the form hemp seed oil or B2, ketoprofen or ibuprofen (Advil, Mortrin). This list is not an exhaustive one.  A person that has liver or kidney problems might also produce a false-positive.

Cannabis is one of the drugs included in the SAMHASA 5 test. This is a panel of drugs that the federal government requires a certain companies to use on their employees. Many other employers use it as well and this panel is testing for the substance THC.