While NORML strongly opposes drug use on the job, we think no one should be forced to submit to urine testing, especially for marijuana. Aside from launching a legal challenge, your best defense against urine testing is to be clean. Unfortunately, this may be difficult since urine tests may detect marijuana 1-5 days after an occasional use, 1-3 weeks in regular users, and 4-6 weeks in multiple daily users. Since urine tests do not detect the psychoactive ingredient of marijuana, THC, but rather other, nonactive metabolites, they in no way measure impairment; nonetheless, this fact is of no account to employers in today’s anti-drug hysteria. If you are on the job market, it is prudent to expect being tested and avoid marijuana. However, recognizing that many of you may face drug testing on short notice, we offer the following advice for emergencies with our best wishes (but no promises!).
DON’T RELY ON EXCUSES: Although urine tests are far from infallible, it is difficult to challenge positive test results. “False positives,” in which workers are wrongfully accused of marijuana use, are highly unlikely so long as labs exercise proper care (however, not all labs do this). The standard procedure is to first screen the samples with an immunoassay test (e.g., EMIT® or RIA®), then confirm positive results with the more accurate gas chromatograph mass spectrometer (GCMS). This virtually eliminates the chance of false positives in exchange for a relatively high rate of “false negatives,” where drug use is not detected. The sensitivity of the test is determined by the concentration of metabolites it is set to detect: for the Dept. of Transportation, the standard cutoff is 50 nanograms/milliliter (ng/ml).
While you’re loading up on water before the test, you may also want to take a large dose (50-100 milligrams) of vitamin B-2, available in B-complex multivitamins. The purpose of this is to color your urine yellow, since otherwise you are likely to produce clear, watery urine, which makes some collectors suspicious (contrary to rumor, vitamin C won’t help). In rare instances, some labs will reject a sample for being too watery; in this case, however, they will typically give you a second chance. Wait until your test results have been confirmed before indulging in compromising behavior.
Efficacy: Urine testing has never been scientifically shown to be safe or effective at improving workplace safety or productivity, and studies indicate that the great majority of drug-positive workers are just as reliable as others (John Horgan, “Test Negative,” Scientific American, March 1990; Dr. John Morgan, “Impaired Statistics and the Unimpaired Worker,” The Drug Policy Letter, May/June 1989). Medically, the consensus of expert opinion is that drug tests are an inherently unreliable indicator of drug impairment (Consensus Report, National Institute on Drug Abuse, Journal of the American Medical Association, Nov. 8, 1985). Dr. George Lundberg of the American Medical Association has called them “Chemical McCarthyism” (editorial, Journal of the American Medical Association, Dec. 5 1986).
BLOOD TESTS: In some situations, including accidents and roadside sobriety checks, blood tests may be used. Blood tests are a much better gauge of current impairment than urine tests because they detect the actual presence of THC in the system; however, they can be sensitive to other metabolites as well. Blood tests generally register positive for just a few hours after smoking, though heavy chronic smokers may be positive for a couple of days. Less sensitive are saliva tests, which register positive for about 2-4 hours after smoking. If you have used marijuana in the last few days but are not currently under the influence, you should insist on a blood (or saliva) test instead of a urine test if at all possible, since you are more likely to turn up clean. On the other hand, if you have smoked recently, you may do better to take a urine test, since this will at least leave open the question as to whether you were under the influence. Also, urine doesn’t turn positive until several minutes after smoking.
TEST YOURSELF: Many drug abuse clinics offer urine testing for a fee. Home test kits are available from companies such as Liberty Research and Instant Diagnostics. Beware: drug urine levels can fluctuate up and down during the day.
“Passive smoking” of marijuana is not an acceptable excuse at the 50 ng/ml level, since only in extreme circumstances can a non-smoker absorb enough pot to test urine positive (e.g., being stuck in a closet full of heavy smokers for hours). However, passive exposure may result in positive tests at 25 ng/ml or lower.
WASH YOURSELF OUT: The general strategy for passing urine tests is to increase your fluid intake and urine flow so as to dilute the concentration of drugs in the sample below the threshold of detection. An hour or two before the test, you should fill your bladder with fluids – as much as you can drink. Water is fine – contrary to popular rumor, there is NO evidence that goldenseal, vinegar, niacin, or vitamin C help. However, high-dosage aspirin may reduce the sensitivity of the EMIT urine test for pot (only). Many people wash themselves out for several days in advance by drinking a lot and exercising, but there is no reason to think this is useful. In no case should you give your first urine of the morning, since drug metabolites tend to build up during your sleep.
You can boost your fluid output by taking diuretics, which stimulate urination. Weak diuretics include coffee, cranberry juice, certain health food products and over-the-counter pills for pre-menstrual water retention.
NORML – Working to Reform Marijuana Laws Dealing With Urinalysis on Short Notice While NORML strongly opposes drug use on the job, we think no one should be forced to submit to urine testing,