The Connection Between Urine Tests and Medical Marijuana

Overview of Medical Marijuana

Marijuana has a long history of medicinal use dating back to 28th century B.C. in China. Medical marijuana has been found to be effective in reducing intraocular pressure. It is also found to have antibiotic, anticonvulsant, antidepressant, analgesic, antispasmodic, and appetite stimulant effects. Medical marijuana consists of isometric tetrahydrocannabinols (THC), cannabinol, and cannabidiol. Medical marijuana is now available for restricted use in the treatment of iatrogenic anorexia, especially that associated with oncologic chemotherapy and radiation therapy.

Drug Urine Tests and Medical Marijuana

The issue of drug urine tests and medical marijuana usage is still under debate. Most of the employers under federal regulations require employees to take a mandatory urine drug test either before recruitment or following recruitment. The Department of Health and Human Services has issued the Substance Abuse and Mental Health Services Administration (SAMHSA) guidelines for federal workplace drug testing programs.

Delta-9-tetrahydrocannabinol (THC) is the primary psychoactive substance in marijuana plant. Immunoassays are used to initially screen urine specimen for THC. For positive results, the sample has to be retested again to confirm the findings using gas chromatography – mass spectrometry (GC-MS) methodology. The initial screening cutoff level is 50 ng/ml. The GC/MS cutoff level is 15 ng/ml. Daily user will remain positive at the initial cutoff of 50 ng/ml for about 7 to 30 days after cessation. At the confirmation level of 15 ng/ml, the frequent user will be positive for perhaps as long as 15 weeks. The storage and slow release of the marijuana metabolites from lipid tissues is the reason for this long detection period.

If a patient is taking a prescription drug that may create problems with the drug test, the patient is supposed to report this beforehand. SAMHSA guidelines require that all positive drug tests be reviewed by a medical review officer (MRO). The MRO has the right to excuse legally prescribed drugs.

Preparations for Urine Drug Tests

For passing a urine test, the patient has to increase fluid intake. The patient may drink lot of water about two hours before the urine test. This will dilute the concentration of THC metabolyte in the urine. The patients should not give first urine of the morning as the drug metabolites mostly build up during sleep. The patient should not drink too much water as this might dilute the urine too much and the sample may be returned for being too dilute. Adulteration tests may also be done during testing.

Although many products are marketed as drug screens, their effectiveness has not yet been proved scientifically. Herbal teas are promoted as urine cleansers, but there is no substantial evidence regarding their effectiveness. People can increase their fluid output by taking weak diuretic such as coffee.


California NORML: Drug Testing

The Vaults of Erowid: History of the Medical Use of Marijuana