Truth and Myths About Marijuana

Marijuana is a dry, shredded green, brown or grey mixture of flowers, stems, seeds, and leaves obtained from the hemp plant Cannabis sativa. It comes in over a hundred street names including Herb, Weed, Smoke, Pot, Killer weed, Jane, Greens, Dope, Mary Jane, or Red Dirt, to name a few. The chief active ingredient of the marijuana plant is delta-9-tetrahydrocannabinol (THC) - a chemical property that can change a person's mood. Once THC enters a person's brain, it creates changes in the way an individual behaves and experiences what is commonly referred to as "high."

Screening Cut-off and Detection Time for THC

Detection of Marijuana Use

In all, there are up to 60 cannabinoids found in marijuana with delta-9-tetrahydrocannabinol (THC) being the primary psychoactive ingredient. Most users smoke marijuana in hand-rolled cigarettes called joints; whereas, some use pipes or water pipes called bongs. Marijuana is also used to brew tea and sometimes is mixed into foods.

When marijuana is smoked, THC rapidly travels from the lungs into the bloodstream, which carries the chemical to organs throughout the body, including the brain. The effects of smoked marijuana can last from 1 to 3 hours. If marijuana is consumed in foods or beverages, the effects appear later-usually in 30 minutes to 1 hour-but can last up to 4 hours.

There are several different ways to detect marijuana metabolites in the person's body, including urine drug test, saliva drug test, hair follicle drug test, and blood test. A urine test is the most popular type of drug testing widely used in schools, government agencies, private institutions, hospitals, law enforcement, and so on. Urine drug testing is capable of detecting the THC component in the individual's system for days or weeks after use - depending on the usage/dosage.

Urine Drug Test for Marijuana

Urine is derived from the blood, as the kidneys eliminate chemicals of all kinds, including alcohol, from the blood. Because the kidneys concentrate chemicals, including drug chemicals, the drug detection window for urine is a bit longer than for the blood.

The urinary concentrations of THC are very difficult to interpret due to variables such as dosage of THC ingested, the frequency of use, the timing of urine collection relative to last exposure to marijuana, the rate of release of stored cannabinoids in adipose tissue, and an individual's hydration state. Therefore, it is important to understand that the detection of THC metabolites in the urine is only an indication of past marijuana uses and is not related to the degree of intoxication or impairment.

One of the major controversies surrounding urine drug testing is that it's easier to adulterate. Adulteration usually starts at what is normally termed as "bathroom problem." Unfortunately, there are a variety of strategies used to cheat on urine samples; hence, it is advised by employers and other institutions performing urine drug testing to conduct sample collection under direct supervision. In some cases, urine collection for a drug test is done in bathrooms that blue dye added to the water or that have had all water supplies cut off to discourage the dilution of urine samples and substitution of someone else's urine.

Below are the advantages and disadvantages of urine drug test as proposed by The Hazelden Betty Ford Foundation and from other existing literature.

Advantages of Urine Drug Testing:

• Urine is the most widely used sample for drug testing; therefore, urine testing has the largest body of experience and has been subject to the greatest legal review.
• The per-test cost for urine is the lowest among all other sample types.
• When using urine testing, the school has the largest number of potential suppliers of test for on-site and laboratory drug testing.
• Urine drug tests are easier to store and are safe for environmental disposal.
• Gloves and sterile cups are usually included; thus there's no need for any additional tools.
• They deliver fast and accurate results.

Disadvantages of Urine Drug Testing:

• Urine is the sample that is most easily cheated on.
• Urine has a short drug detection window, typically one to three days after drug use, although some urine tests are negative 12 hours after the last drug use.
• Urine must be handled with gloves to prevent the spread of infectious disease.
• Bathroom facilities are required to conduct the test, which may not be always monitored.
• Urine drug testing kits are somewhat invasive.

Hair Drug Test for Marijuana

Hair follicle drug testing is regarded as a revolutionary method of testing for drugs using hair strand analysis. It is currently used by companies in various sectors for highly safety-critical positions where there is zero tolerance for drug usage including forensics, maritime, insurance, schools, and law enforcement.

The biology of hair is far different from the biology of urine. Nevertheless, hair follicle testing is just as reliable as a urine test. Hair contains drugs that were in the blood, including illicit substances, when each tiny bit of hair was built. Since head hair grows at a fairly steady rate of about half an inch a month, the hair extending about one and one-half inches from the head contains a virtual tape recording of what was in the blood during the ninety days before the hair sample is taken.

Hair analysis tests can detect a longer period of drug use compared to more traditional forms of random drug testing. A standard hair follicle drug test covers a period of 30 to 90 days of donor's drug use. Using a small sample of hair cut near the scalp, hair analysis evaluates the level of drug metabolites embedded inside the hair shaft. If no head hair is available, body hair can be used. This provides a longer window of detection of approximately 365 days. Bleaches, shampoos and external contaminants have no known impact on the results.

Hair drug tests are more likely to detect regular versus occasional marijuana use. The 2006 publication "Cannabinoid concentrations in Hair from Documented Cannabis Users," revealed that ingested cannabis was less likely to be detected than smoked marijuana.

Advantages of Hair Drug Test:

• The marijuana detection period is longer - usually up to 90 days.
• Specimen collection is easier, with no bathroom problems.
• The specimens are not messy to handle or ship, and there are no infectious disease problems when handling hair samples.
• In the case of disputed results, it's easy to retest within about 2 weeks of the initial test.
• Hair samples are easy to store and collection is non-invasive.

Disadvantages of Hair Drug Test:

• Hair drug testing kits cost more than urine or saliva drug testing.
• Fewer companies provide hair test.
• For marijuana, the tests detect only repeated, regular use.

Saliva Drug Test for Marijuana

Saliva drug testing is a fairly new technique, wherein a swab or a piece of absorbent material is placed in the donor's mouth for about one minute and then removed and placed in a collection container. The results are read within a few minutes, and if the donor tested positive, the positive result is sent to a laboratory for confirmation testing. However, despite being effective in identifying the recent use of commonly studied drug, saliva drug testing is relatively insensitive to marijuana.

Many health experts and researchers continue to conduct studies to establish solid theories about saliva drug test's reliability. In general, the use of saliva as a sample specimen is limited in scope because of its shorter detection time.

Advantages of Saliva Drug Test:

• Saliva/Oral Drug Testing can be collected and tested on site with no intrusion of privacy.
• They are difficult to adulterate.
• Samples can be collected easily in virtually any environment.
• Results can be read in minutes without the need for lab analysis.
• They can detect a wide range of drug substances like ethanol, amphetamines, barbiturates, benzodiazepines, caffeine, cocaine, THC, opiates, and phencyclidine.
• They are able to indicate recent drug use for non-smoked drugs.
• They are suitable for workplace, compliance and forensic testing.

Disadvantages of Saliva/Oral Drug Testing:

• Saliva drug test is not sensitive to marijuana.
• It offers small detection window - usually 12 to 24 hours.
• Drug concentrations may be low and subsequently difficult to analyze.
• Confirmatory analysis requires sensitive analytical facilities.
• The sample size is limited.

Marijuana Detection Period

According to American Society of Addiction Medicine's Principles of Addiction Medicine, the average elimination half-life of THC is between 20 and 30 hours. THC has a highly lipophilic nature and is stored in fatty tissues, where it is slowly released back into the circulation.

Urine screening tests for marijuana typically use cutoffs of 20, 50 or 100 ng/mL. The current federally mandated cutoff for workplace drug testing is 50 ng/mL. Most laboratories measure the inactive metabolite THC-COOH which can be quantitated in blood, urine, hair, oral fluid or sweat using chromatographic techniques as part of a drug use testing program or a forensic investigation of a traffic or other criminal offense.

The chart below indicates the approximate detection periods of marijuana in urine drug test based on usage:

The most common analytical methods used to detect cannabinoids in urine include immunoassays (EIA, RIA, and FPIA), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), high-pressure liquid chromatography (HPLC), and thin layer chromatography (TLC).

At present, synthetic drug test kits can detect the presence of synthetic cannabinoids like JWH-018 and JWH-073, which possess biological activities similar to 9-tetrahydrocannabinol (THC) - the primary component of marijuana. In this synthetic marijuana urine laboratory test, the compounds are identified down to levels of approximately 0.1 ng/mL for most of the diagnostic metabolites. JWH-018 and JWH-073 metabolites can be detected in urine up to 72 hours.