Testing Types
Urine Drug Testing
When an employer requests a drug test from an employee the employee is typically instructed to go to a collection site. The employee’s urine is collected at a remote location in a specially designed secure cup, sealed with a tamper resistant tape, and sent via express delivery service to a testing laboratory to be screened for drugs (typically SAMHSA 5 panel).
The first step at the testing site is to split the urine into two aliquots. One aliquot is first screened for drugs using an analyzer that performs immunoassay as the initial screen. If the urine screen is positive then another aliquot of the sample is used to confirm the findings by gas chromatography – mass spectroscopy (GC-MS) methodology. All test results are relayed to an MRO (Medical Review Office) where a medical physician reviews the results. If the result of the screen is negative, the MRO informs the employer that the employee has no detectable drug in the urine. However, if the test result of the immunoassay and GC-MS are non-negative and show a concentration level of parent drug or metabolite above the established limit, the MRO contacts the employee and to determine if there is any legitimate reason – such as a medical treatment or prescription.
About 5% of the all pre-employment urine samples tested in the U.S. turn out positive for drugs. The percentages are much higher for post-accident and/or reasonable suspicion testing.
The efficacy of urine testing is debatable due to systematic cheating (adulteration and/or substitution of the specimen). Sample substitution and adulteration occur frequently, and both are effective methods of avoiding would-be positive tests. While most laboratories performing drug screens test for adulterants routinely, they can not keep pace with the various forms of adulterants available. [14]
Adulterants can be classified into two categories. The first category includes classic adulterants comprising household substances and other chemicals such as chlorine bleach, liquid drain cleaner, white vinegar, glutaraldehyde, sodium nitrite, and pyridinium chlorochromate. The second category includes commercial adulterants, which can be purchased from certain specialty stores (so-called “head shops”), through magazine advertisements, or via the Web. This second class of adulterants includes brand names such as Urine Luck version 6.3, Stealth, Clean-X, Klear, Purafyzit, Instant Clean, Krystal Kleen, and UR’n Kleen. Some of the commercial adulterants represent a repackaging of classic adulterants. One adulterant, for example, Klear, is made of nitrite and affects the tetrahydrocannibinol (THC) confirmation process but not the immunoassay process. Urine Luck 6.3 is actually hydrofluoric acid, which is an oxidant not generally available in the classic adulterants category because of its corrosive nature. Stealth is an enzyme system that generates hydrogen peroxide.
Abusers can also drink 1 to 2 liters of water to successfully dilute the concentration of drug metabolites in their urine below detectable thresholds, without risking detection. While this results in clear samples that may be rejected on the grounds of being too dilute, the practice is typically successful. A B vitamin will make urine yellow despite this practice of waterloading. Specific gravity testing can be done to identify whether or not the sample is of dilute nature. Vitamin B3 (niacin) is also frequently used for its reported “flushing” effect, though this is also of disputable adeptness.
Adulteration tests can detect the use of some of these “detox” products. Adulteration tests analyze the properties of the urine to identify if the sample is abnormal. Such properties include the pH and specific gravity of the urine. They also test the level of creatinine, nitrite, glutaraldehyde, specific gravity, bleach and pyridinium chlorochromate.
Also, the wide availability of at-home drug screens allows an individual to take their own test before they receive one, thus knowing the results ahead of time- giving the user further opportunity to dilute the sample or to find a substitute.
New regulations from the U.S. Department of Transportation are requiring that specimens which indicate a low temperature or show signs of adulteration be admitted with a second specimen from the donor, which is collected under direct observation. That is, the donor voids in full view of the collector or observer. The new regulations also require that the donor raise and lower clothing and turn around in front of the collector or observer to show that the donor is not in possession of any device or substance with intent to falsify the test. In several states, it is illegal to sell or possess such a device or substance.
Random Drug Testing
Random drug testing is the most effective format. In the USA, random drug testing is used by a growing number of corporations, drug rehab centers, prisons, the military, police and fire departments, government agencies, and more recently, schools.
It may also be used on teens by their parents, or mandated to be performed at school. The objective of a random drug test is deterrence, as the threat of detection is much higher versus other testing methods. Various random selection methods are used, ranging from drawing names out of a hat to using random number generators.
Critics of random testing claim that random drug testing introduces a presumption of guilt, and is a violation of privacy if the drug user is not actually intoxicated during working hours. In addition, urine-based random testing is more likely to catch cannabis users, since THC metabolites are fat soluble and have a longer duration in the body than those of many other drugs.
Pre-employment Drug Testing
This is by far the most common type of drug test used by businesses, however, it is also the least effective. It is considered to be an “intelligence test” by drug testing professionals. It has the advantage of being inexpensive, since only one test per employee needs to be paid for by the company. However, since most pre-employment drug testing is urine-based and subject to sample adulteration or substitution, the effectiveness of this approach has been questioned by federal legislators. Some organizations have a witness in the room at the time of the testing, but the privacy implications of this, as well as the potential for shy bladder syndrome has limited the use of witnesses outside jails and drug treatment programs. Companies and testing centers that do not use witnesses normally disconnect sources of water from the testing room to discourage dilution, and if there is water in the toilet, it is dyed blue. Other countermeasures, such as making the donor change into a gown, may also be used.
Post-incident Drug Testing
Post-incident drug testing is not a very commonly administered test compared to the other two, but the financial ramifications of not testing employees after an accident (or other incident) on the job makes this test worthwhile for most businesses.
The point of this test is not necessarily to cause the employee to lose his or her job, but rather to protect the company from liability in the event that the individual is under the influence at the time of the accident. If drugs or alcohol are detected in any significant quantity, the argument can be made in court that the individual was intoxicated on the job, and for that reason, the company should not be held liable for injuries sustained by the employee. This argument, however, can only reasonably be made if blood or oral fluid / saliva testing is used. Urine, hair, or sweat based testing can only detect past drug use. Depending upon the facts of each case, this may help a company avoid litigation completely or may do nothing to help their case. DUI testing would also fall into this category. Another time this type of test may be used is if an employee shows up for work intoxicated, has alcohol on his or her breath, or appears to be impaired in some other way.
The sample should follow chain of custody requirements and should always be sent to a lab after collection. Positive on-site tests that may affect an employee’s position or situation should always be followed up with a laboratory test before any action is taken against the employee.
Hair Testing
Hair drug testing is a method that can detect drug use over a much longer period of time,[25] and is often used for highly safety-critical positions where there is zero tolerance of illegal drug use.[26] Standard hair follicle screen covers a period of 30 to 90 days. The growth of hair is usually at the rate of 0.5 inches per month. The hair sample is cut close to the scalp and 80 to 120 strands of hair are needed for the test. In the absence of hair on the head, body hair can be used as an acceptable substitute.[25] Even if the person being tested has a shaved head, hair can also be taken from almost any other area of the body. This includes facial hair, the underarms, arms, and legs or even pubic hair. Because body hair grows at a different rate than head hair, the time frame changes, with scientists estimating that drug use can be detected in body hair for up to 12 months. Currently, most entities that use hair testing have prescribed consequences for individuals removing hair to avoid a hair drug test.
The claim that a hair test cannot be tampered with has been shown to be debatable. One study has shown that THC does not readily deposit inside epithelial cells so it is possible for cosmetic and other forms of adulteration to reduce the amount of testable cannabinoids within a hair sample.