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Article Summary

The ABC's of Marijuana Drug Testing

For any child growing up, learning their ABCs is an essential step toward gaining a greater understanding of the world in which they live. In the Orwellian world of random workplace drug testing, cannabis consumers must learn another equally important set of ABCs in order to successfully navigate their way through life: the ABCs of drug testing.

Details of Marijuana Drug Testing

A – adulterant

An adulterant is defined as any substance that, when added to an urine specimen, alters it in such a way to yield a negative result (aka a "false negative"). Common adulterants like bleach, Visine, or glutaraldehyde, as well as many chemical oxidants such as nitrates (e.g. Whizzies, Klear), are screened for by the drug testing industry and are readily identifiable. Nevertheless, "spiking" a sample still remains a viable option for those who are willing to risk it, as there is no shortage of new, alternative adulterants promising to "beat" an urine test while avoiding the watchful eye of the drug testers.

B – blood testing

Blood tests, unlike urinalysis, detect the presence illicit drugs, not inactive drug metabolites. In general, THC only remains detectable in the blood of cannabis consumers for a few hours (though low, residual levels may be detected in chronic smokers for up to 12-24+ hours if more sensitive technology is used). Because of this narrow detection window, blood tests are typically only administered in the workplace post-accident in order to estimate recent cannabis consumption. Therefore, most after-hours consumers have little to fear from a blood screen.

C – creatinine

Creatinine is a normal byproduct of muscle metabolism that is present in urine at specific levels. Creatinine levels are one of several "benchmarks," including pH, color, and specific gravity, assayed by urinalysis examiners to weed out diluted samples. In response, would-be drug test "thwarters" engage in several tried-and-true methods – including consuming Vitamin B, riboflavin, and even creatine supplements – to maintain these levels within the ranges acceptable to drug testing labs.

D - diuretic

A diuretic is defined as any substance that increases urine output. Caffeine, cranberry juice, and most "quick flush" herbal teas marketed as "detoxifiers" are diuretics. Water, though also effective in helping marijuana smokers "beat" the test, is not a diuretic. Consuming diuretic fluids just prior to taking an urine test dilutes the concentration of drug metabolites in the sample below the threshold of detection. However, this effect is only temporarily. Because marijuana’s primary metabolite is fat soluble, consuming no amount of fluids – even diuretic fluids – will permanently "flush" it out of one’s system. Once the short-term effect of the diuretic wears off and the urine returns to its proper concentration, cannabis metabolites will once again become readily detectable to snooping drug screeners.


EMIT is the acronym for enzyme multiplied immunoassay technique, the cheapest and most common drug screen used in workplace drug testing. EMIT testing is typically used by employers as a preliminary drug screen because the test is prone to incorrect results. In general, occasional consumers (as in, once or twice per week) should have little trouble passing an EMIT test – which typically uses a 50 ng/ml cut-off for the THC-COOH metabolite – as long as they have had one or two days of abstinence prior to taking the test.

F- false positive

"False positives" are instances where the metabolite of a legal prescription drug or other substance (e.g. poppy seeds) tests positive for the metabolite of an illicit drug. Because marijuana’s metabolite is fairly unique, "false positives" are rare. However, at least one common prescription medication, Protonix (pantoprazole sodium), warns of "false positives" for cannabis. Over-the-counter ibuprofen products (e.g. Advil) will not test positive for marijuana on modern drug screens, but numerous OTC cold remedies may trigger "false positive" results for amphetamines, primarily on the EMIT test. Consequently, employees subject to random testing should insist that all positive test results be substantiated by follow-up testing, .


GCMS is the acronym for gas chromatography/mass spectrometry, better known in layman’s terms as the "confirmation test." Most workplace drug testing programs (including regulations for all US federal jobs) mandate all positive EMIT tests be confirmed by GCMS to eliminate the likelihood of "false positive" test results. Because GCMS tests typically use a low 15 ng/ml cut-off for marijuana metabolites, frequent cannabis consumers are prone to testing positive on this test for two to three weeks (or even longer in some extreme cases) after their last encounter.

H – hair follicle testing

Hair strand testing detects the presence drug metabolites that have passively diffused from the blood stream to the base of the hair follicle. Critics of this troublesome technology rightly argue that the test is biased by both race (e.g., The tests is more sensitive to minorities and people with darker-colored hair) and age (e.g. Grey hair uptakes fewer metabolites than normally colored hair). While studies have indicated that marijuana metabolites do not bind sufficiently to hair compared to other drugs such as cocaine – read: occasional cannabis consumption may go undetected on a hair test – recent research also indicates that exposure to high humidity will rapidly break down marijuana metabolite levels in the hair of heavier smokers, increasing the likelihood of a negative result.

I – iodine

Iodine is a popular adulterant used by drug test "thwarters" forced to submit to urinalysis on short notice. While scientific studies have demonstrated that iodine destroys certain drug metabolites (e.g. morphine) on contact, it is less efficient (though still somewhat effective) at eliminating marijuana metabolites.

J – junk science

Despite the prevalence of workplace drug testing programs in the US, there is hardly any scientific evidence demonstrating their efficacy. "The preventive effects of drug testing have never been demonstrated," concluded an exhaustive review by the National Academy of Sciences. "There is as of yet no conclusive scientific evidence from properly controlled studies that employment drug testing programs widely discourage drug use or encourage drug rehabilitation."

K – Klear

For years Klear was one of the most popular and successful name-brand adulterants available on the market. Analyses by the drug testing industry eventually revealed Klear to be potassium nitrate, a discovery that led many labs to begin screening all of their urine samples for the presence of nitrate additives. Most drug testers now treat a positive test result for nitrates the same as if the sample tested positive for illegal drugs. (Klear has since been reformulated and is now marketed as NuKlear.)

L – Lasix

Lasix (ferosemide) is one of many stronger diuretics available by prescription. While non-prescription use of Lasix can potentially be hazardous to health if taken over long lengths of time, its use has been popular for more than two decades by those subject to random workplace drug tests on short notice.

M – metabolite

Drug metabolites are compounds produced from chemical changes of a psychoactive substance in the body, but they are not necessarily psychoactive themselves. The presence of drug metabolites – not the presence of illicit drugs – is the primary indicator of drug use in workplace drug testing programs, such as urinalysis and hair testing.

N- Nanogram

A nanogram is one billionth (1/1,000,000,000) of a gram. Drug testers rely on this microscopic unit of measurement (e.g. 15 ng/ml) to measure residual levels drugs and/or drug metabolites in blood, urine, hair and/or saliva.

P – papain

Papaine is an enzyme found in the papaya fruit. Papaine has been gaining popularity among would-be drug test "thwarters" after a recent study in The Journal of Forensic Toxicology reported that adding it to urine reduces the presence of marijuana metabolites and goes undetected by standard laboratory procedures.

Q – Quest Diagnostics

Quest Diagnostics is one of the largest drug testing companies in existence, performing more than 8 million drug tests annually. In 2005, Quest Director of Science and Technology Barry Sample testified before the US Congress in favor of legislation to criminalize the production and sale of certain products designed to influence workplace drug test results. Is H20 next on the Congressional hit list?

R – Reagan, Ronald

Ronald Reagan was the 40th President of the United States and is arguably the man most responsible for the modern explosion in random, workplace drug testing programs in the United States. Reagan signed Executive Order 12564 in 1986, which mandated federal employees to be "drug free" on and off the job, and spawned the emergence of suspicionless drug testing in the private sector.

S – saliva testing

Saliva testing, like blood testing, detects the presence of parent drugs – not their inactive metabolites. Consumers take heart: THC is highly difficult to identify in oral fluids, as only a minute amount of the drug is excreted into the saliva. As a result, most current saliva testing technology typically only detects the presence of cannabis for a period of approximately one to two hours following drug ingestion, and sometimes not at all.


THC-COOH, though not psychoactive, is the primary marijuana metabolite screened for in workplace drug testing. While most drug metabolites are water-soluble and are excreted rapidly from the body, THC-COOH, is fat-soluble and thus exits the body slowly. For infrequent cannabis users, THC-COOH remains detectable in urine for several hours after one-time use; however, it’s commonly detectable on a standard urine screen for days or even weeks after past use in regular smokers.

U – urinalysis

Of the estimated 55 million drug tests performed annually in the United States, approximately 90 percent of these are urine tests. While often inaccurately referred to by employers and drug testers as an impairment test, urinalysis can not detect the presence of any illicit drugs – including marijuana – and can only identify the presence of non-psychoactive drug metabolites indicating that a substance has been previously consumed at an unspecified point in time. Unfortunately for cannabis consumers, pot’s primary metabolite THC-COOH is fat soluble, and may remain detectable in urine for days and sometimes two-to-three weeks after past use in regular smokers. Fortunately, most standard urine tests can be easily influenced by dilution.

V – von Rabb

In 1989, the US Supreme Court for the first time upheld the use of suspicionless drug testing of employees in the workplace. The Court ruled 5-4 in the case, National Treasury Employee's Union v. von Rabb, that testing employees without cause does not violate the U.S. Constitution's Fourth Amendment protections against unreasonable searches, paving the way for an unprecedented wave of unnecessary workplace drug testing programs. The US Supreme Court has since ruled to allow the random drug testing of student athletes as well as students who participate in non-athletic extracurricular activities, such as band or the chess club.

W – water

Facing a drug test on short notice? Remember the phrase: "Just add water." Drinking large quantities of water (e.g. 120 fluid oz) prior to taking an urine test is the easiest, cheapest, and according to recent testimony before Congress by the US Department of Health and Human Services, still remains one of the most effective methods of beating an urine test. In desperate circumstances, water may also be added directly to a sample to dilute the specimen.

X – unknown

A positive urine test (or hair test) result does not indicate user impairment, nor can it estimate when a particular substance was consumed. That’s why even the US Department of Justice concedes that a positive drug test result for the presence of a drug metabolite "does not indicate ... recency, frequency, or amount of use; or impairment."

Y – yellow

Considering playing the dilution game? Fear the clear. Too often, diluted urine samples lose their yellow color. Fortunately, doses of Vitamin B will help restore urine to its natural color and help avoid the gaze of hawk-eyed drug testers.

Z – zinc

Despite the popularity of urinalysis, the majority of THC metabolites are actually eliminated from the body by way of the feces, not urine. Zinc sulfate is believed to bond with THC metabolites, rendering them too large to filter through the kidneys. In theory, these "bonded" metabolites are then redirected to the feces. In practice, however, the use of zinc sulfate has yielded only mixed results for those hoping to bypass the system.

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