Drug test

For other uses, see Drug testing.

A drug test is a technical analysis of a biological specimen - for example urine, hair, blood, sweat, or oral fluid / saliva - to determine the presence or absence of specified parent drugs or their metabolites. Major uses of drug testing are to detect the presence of performance enhancing steroids in sport or for drugs prohibited by laws, such as cannabis, cocaine and heroin.

Detection periods

The following chart from LabCorp gives approximate detection periods for each substance by test type.

The detection windows depend upon multiple factors - drug class,amount and frequency of use, metabolic rate, body mass, age, overall health, and urine pH. For ease of use, the detection times of metabolites have been incorporated into each parent drug. For example, heroin and cocaine can only be detected for a few hours after use, but their metabolites can be detected for several days in urine. In this type of situation, we will report the (longer) detection times of the metabolites.

• NOTE 1: Oral fluid or saliva testing results for the most part mimic that of blood. The only exceptions are THC and benzodiazepines. Oral fluid will likely detect THC from ingestion up to a maximum period of 18–24 hours. Low saliva:plasma ratio continues to cause difficulty in oral fluid detection of benzodiazepines
• NOTE 2: Urine cannot detect current drug use. It takes approximately 6–8 hours or more post-consumption for drug to be metabolized and excreted in urine. Similarly, hair requires two weeks, and sweat, seven days.

Approximate values for detection periods

Substance	Urine	Hair	Blood / Oral Fluid
Alcohol	6–24 hours	up to 90 days	12–24 hours
Amphetamines (except meth)	1 to 3 days	up to 90 days	12 hours
Methamphetamine	3 to 5 days	up to 90 days	1–3 days
MDMA (Ecstasy)	24 hours	up to 90 days	25 hours
Barbiturates (except phenobarbital)	1 day	up to 90 days	1 to 2 days
Phenobarbital	2 to 3 weeks	up to 90 days	4 to 7 days
Benzodiazepines	Therapeutic use: up to 7 days. Chronic use (over one year): 4 to 6 weeks	up to 90 days	6 to 48 hours
Cannabis	3 to 7 days, up to >30 days after heavy use and/or in users with high body fat	up to 90 days	2–3 days in blood, up to 2 weeks in blood of heavy users However, it depends on whether actual THC or THC metabolites are being tested for, the latter having a much longer detection time than the former.
Cocaine	2 to 5 days with exceptions for certain kidney disorders	up to 90 days	2 to 5 days
Codeine	2 to 3 days
Cotinine (a break-down product of nicotine)	2 to 4 days	up to 90 days	2 to 4 days
Morphine	2 to 4 days	up to 90 days	1 – 3 days
Heroin	3 to 4 days	up to 90 days	1– 2 days
LSD	24 to 72 hours (however tests for LSD are very uncommon)	up to 3 days	0 to 3 hours
Methadone	3 days	up to 97 days	24 hours
PCP	3 to 7 days for single use; up to 30 days in chronic users	up to 90 days	1 to 3 days

Common types of drug tests

Urine drug screen

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 spectrometry (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.

On-site instant drug testing is becoming more widely used in states allowing it as a more cost-efficient method of effectively detecting drug abuse amongst employees, as well as in rehabilitation programs to monitor patient progress. These instant tests can be used for both urine and saliva testing. Although the accuracy of such tests varies with the manufacturer, some kits boast extremely high rates of accuracy, correlating closely with laboratory test results.

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 oxidant not generally available in the classic adulterants category because of its corrosive nature. Stealth is an enzyme system that generates hydrogen peroxide.

There are many reasons that an individual may produce a dilute urine specimen, the majority of which are the result of normal physiological processes (e.g. pregnancy, diabetes, a diet high in water etc.) specific circumstances, or an individual's personal characteristics (e.g., body type, sex, race, athleticism). Because dilute specimens are relatively common for these reasons, neither the HHS Guidelines nor the U.S. Department of Transportation Procedures for Transportation Workplace Drug and Alcohol Testing Programs permit further processing of negative and dilute specimens. Specific gravity testing can be done to identify whether or not the sample is of dilute nature.

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.

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.

Hair testing

Analysis of hair samples has many advantages as a preliminary screening method for the presence of drugs. The advantages of hair analysis include the non-invasiveness, low cost and the ability to measure a large number of, potentially interacting, toxic and biologically essential elements. Especially in the United States hair testing is increasingly being used by employers to test employees for potential illegal drug consumption.

Tests detecting both FAEE and EtG levels have been used by UK courts. Trimega is the 1st company to commercialise this testing in both the UK and US judicial system is Trimega Laboratories of London. The company also is the only company in the world that can provide testing of both ETG and FAEE at the same time therefore increasing accuracy of the results.

Hair absorbs special markers called fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG) into its structure, which remain in the hair indefinitely. These markers are only produced when there is alcohol in the bloodstream, such that the more markers there are, the more alcohol you have consumed.

Alcohol

In contrast to other drugs consumed, alcohol is not deposited directly in the hair. For this reason the investigation procedure looks for direct products of ethanol metabolism. The main part of alcohol is oxidized in the human body. This means it is released as water and carbon dioxide. One part of the alcohol reacts with fatty acids to produce esters. The sum of the concentrations of four of these fatty acid ethyl esters (FAEEs: ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) are used as indicators of the alcohol consumption. The amounts found in hair are measured in nanograms (one nanogram equals only one billionth of a gram), however with the benefit of modern technology, it is possible to detect such small amounts. In the detection of Ethyl Glucuronide, or EtG, testing can detect amounts in picograms (one picogram equals 0.001 nanograms).

However there is one major difference between most drugs and alcohol metabolites in the way in which they enter into the hair: on the one hand like other drugs FAEEs enter into the hair via the keratinocytes, the cells responsible for hair growth. These cells form the hair in the root and then grow through the skin surface taking any substances with them. On the other hand the sebaceous glands produce FAEEs in the scalp and these migrate together with the sebum along the hair shaft (Auwärter et al., 2001, Pragst et al., 2004). So these glands lubricate not only the part of the hair that is just growing at 0.3 mm per day on the skin surface, but also the more mature hair growth, providing it with a protective layer of fat.

FAEEs (nanogram = one billionth of a gram) appear in hair in almost one order of magnitude lower than (the relevant order of magnitude of) EtG (picogram = one trillionth of a gram). It has been technically possible to measure FAEEs since 1993, and the first study reporting the detection of EtG in hair was done by Sachs in 1993.

In practice, most hair which is sent for analysis has been cosmetically treated in some way (bleached, permed etc.). It has been proven that FAEEs are (surprisingly) not significantly affected by such treatments (Hartwig et al., 2003a). FAEE concentrations in hair from other body sites can be interpreted in a similar fashion as scalp hair (Hartwig et al., 2003b).

Saliva drug screen / Oral fluid-based drug screen

Saliva / oral fluid-based drug tests can generally detect use during the previous few days. Saliva or oral fluid based drug tests are becoming more prevalent because of their convenience and the fact that they are very difficult to adulterate. Furthermore, on-site oral based tests in particular enable the implementation of random testing programs, proven to be the most effective type of drug screening. Testing is usually performed by employers, for either pre-employment, random, post-accident, reasonable suspicion, or return-to-duty testing. Oral fluid based testing most closely mimics results found with blood and is preferable for detecting on-the-job drug use or in post-accident applications in this case because the degree of intoxication can be approximated based on the amount of substance.

Detection in saliva tests begins almost immediately upon use of the following substances, and lasts for approximately the following times:

• Alcohol: 6–12 h
• Marijuana and hashish (THC): 12–24 h
• Cocaine (including crack): 1 day
• Opiates: Up to 2–3 days
• Methamphetamine ("Tweak," "crank," "ice") and ecstasy (MDMA,) : Up to 2 to 4 days.
• Benzodiazepines: From time of ingestion up to 2 to 3 days
• Amphetamines 3 days
• Phencyclidine (PCP) 3 days

NOTE: Saliva tests are highly sensitive and detection times can vary considerably based on the cutoffs used.

Sweat drug screen

Sweat tests are patches attached to the skin to collect sweat over a long period of time (1-4 Hours). These are almost exclusively used by child protective services, parole departments, and other government institutions concerned with drug use over long periods, when urine testing is not practical.

Drug testing methodologies

The different types of drug tests are tested in very similar ways. Before testing the sample, the tamper-evident seal is checked for integrity. If it appears to have been tampered with or was damaged in transit, the laboratory rejects the sample and does not test it.

One of the first steps for all drug tests is to make the sample testable. Urine and oral fluid can be used "as is" for some tests, but other tests require the drugs to be extracted from urine beforehand. Strands of hair, patches, and blood must be prepared before testing. Hair is washed in order to eliminate second-hand sources of drugs on the surface of the hair, then the keratin is broken down using enzymes. Blood plasma may need to be separated by centrifuge from blood cells prior to testing. Sweat patches are opened up and the sweat collection component is soaked in a solvent to dissolve any drugs present.

Laboratory-based drug testing is done in a two-tiered fashion using two different types of detection methods. The first is known as the screening test, and this is applied to all samples that go through the laboratory. The second, known as the confirmation test, is only applied to samples that test positive during the screening test. Screening tests are usually done by immunoassay (EMIT, ELISA, and RIA are the most common). A "dipstick" drug testing method which could at some future time provide screening test capabilities to field investigators has been developed at the University of Illinois.

After a suspected positive sample is detected during screening, the sample is flagged and tested using the confirmation test. Samples that are negative on the screening test are discarded and reported as negative. The confirmation test in most laboratories (and all SAMHSA certified labs) is performed using mass spectrometry, and is extremely precise but also fairly expensive to run. False positive samples from the screening test will be negative on the confirmation test. Samples testing positive during both screening and confirmation tests are reported as positive to the entity that ordered the test. Most laboratories save positive samples for some period of months or years in the event of a disputed result or lawsuit. For workplace drug testing, a positive result is generally not confirmed without a review by a Medical Review Officer that will normally interview the subject of the drug test.

Types of testing

Anabolic steroids

Anabolic steroids are used to enhance performance in sport and as they are prohibited in most high-level competitions drug testing is used extensively in order to enforce this prohibition. This particularly so in individual (rather than team) sports such as Athletics and Cycling.

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 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 of jails, the military, 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.

Random drug testing

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, and in some countries can be 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.

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.

Post-incident drug testing

Post-incident drug testing is not a very commonly administered test compared to the other. 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.

Diagnostic screening

In the case of life-threatening symptoms, unconsciousness, or bizarre behavior in an emergency situation, screening for common drugs and toxins may help find the cause, called a toxicology test or tox screen to denote the broader area of possible substances than self-administered drugs. The test is usually done within 96 h (4 days) after the estimated time of intoxication. Both a urine sample and a blood sample may be tested. A blood sample is routinely used to detect ethanol/methanol and ASA/paracetamol intoxication. Various panels are used for screening urine samples for common substances, e.g. triage 8 that detects amphetamine, benzodiazepines, cocaine, methadone, opiates, cannabis, barbiturates and tricyclic antidepressants. Results are given in 10–15 min.

Similar screenings may be used in to evaluate the possible use of date rape drugs. This is usually done on a urine sample.

Drug testing methods

Urine drug testing

Urine drug test kits are available as on-site tests, or laboratory analysis. Urinalysis is the most common test type and used by federally mandated drug testing programs, yet likely the least effective.

The main disadvantages of urine-based drug test kits are (1.) the ease at which they can be "cheated" via simple adulteration or substitution, unless specimen collection is directly observed, (2.) inability to detect current / on-the-job drug abuse, (3.) the need for bathroom facilities, and (4.) with respect to SAMHSA-5, or NIDA-5, the inability to test for drugs commonly abused/mis-used in current society.

Saliva drug testing

Saliva (oral) drug test kits are very donor friendly, non-invasive and easy to collect the specimen. There is no need for a bathroom to administer the tests. Saliva drug testing tends to detect recent drug use. Also these drug tests are harder to adulterate than the urine drug tests since the sample can be obtained under direct supervision. Depending on the test, up to 8 different drugs could be detected. This method is the best method for determining recent use and is a potential indicator of impairment.

A disadvantage of saliva based drug testing is that it is not approved by SAMHSA for use with DOT / Federal Mandated Drug Testing. Oral fluid is not considered a bio-hazard unless there is visible blood, however, it should be treated with care.

Spray (sweat) drug testing

Spray (sweat) drug test kits are non-invasive. It is very easy to collect the specimen and no bathroom is needed for taking the specimen. The detection window is long and usually can detect drug use up to a couple of hours. These drug tests are relatively tamper proof since they are hard to manipulate. A laboratory is not required for analysis.

The main disadvantage of spray or sweat based drug testing is the fact that they are open to contamination. Also large variations of sweat production rates of possible donors make some results inconclusive. There is not much variety in these drug tests since they are not as popular as urine or saliva drug testing kits. Their prices tend to be higher per test conducted. One main disadvantage of this testing method is the limited number of drugs that can be detected, and the ability to produce instant results.

Hair drug testing

Hair drug testing can provide a much longer window of detection, which is useful for highly safety-critical positions where there is zero tolerance of drug usage. Even if the person being tested has a shaved head (perhaps in preparation for the test), hair can also be taken from almost any other area of the body. This includes facial hair, the underarms, arms, and legs.

Though it is often claimed that hair test cannot be tampered with, it has been shown that this is simply untrue. For example, 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 .

Legality and ethics of mandatory drugs testing

Drug 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. This bias can potentially lead would-be cannabis users to switch to harder drugs or alcohol, most of which generally have significantly shorter detection times and/or are less likely to be tested for.

United Kingdom

A study in 2004 by the Independent Inquiry into Drug Testing at Work found that attempts by employers to force employees to take drug tests could potentially be challenged as a violation of privacy under the Human Rights Act 1998 and Article 8 of the European Convention of Human Rights. However, this does not apply to industries where drug testing is a matter of personal and public safety or security rather than productivity.

United States

Mandatory drug testing entered American life through two separate historical routes. The first was through the common law system, employing precedents philosophically derived from the idiosyncratic rules governing the "king's forest" and the "king's highway". From these arcane precepts are derived the laws which allow legal authorities to detain and test persons under suspicion of driving under the influence of a psychoactive drug.

The second route was more recently constructed and originated from an incident that occurred in the US Navy. After a plane crashed onto the carrier deck of the USS Nimitz in 1981, killing and injuring dozens of personnel, drug testing was instituted immediately. The results revealed a large substance-using cohort within the ranks of enlisted persons and officers. As a result of this single incident, the Secretary of the Navy instituted an intensive drug testing and regulation program. These interventions were then adopted by other branches of the service over a three-year period. From these actions was derived the concept of a "drug-free workplace". In consultation with his drug-czar, Dr. Carlton Turner, President Ronald Reagan issued Executive Order 12564. In doing so, he instituted mandatory drug-testing for all safety-sensitive executive-level and civil-service Federal employees. This was challenged in the courts by the National Treasury Employees Union. In 1988, this challenge was considered by the US Supreme Court A similar challenge resulted in the Court extending the drug-free workplace concept to the private sector. These decisions were then incorporated into the White House Drug Control Strategy directive issued by President George H.W. Bush in 1989.

Urban legends, myths, and misconceptions

The increasingly common practice of drug testing has led to an increase in the number of drug users looking for ways to beat the tests, and has spawned a number of myths and urban legends as a result. However, this does not stop users from getting creative in their attempts to somehow shorten the detection times and/or mask the contents of their fluid specimens, with varying degrees of success or lack thereof.

Drinking vinegar will help you pass

This legend is one of the oldest ones in the history of drug testing, and is only partly true. Consumption of vinegar will lower the pH of the blood and urine, and drugs that contain amine groups (such as amphetamines) will be cleared out somewhat faster as their water solubility increases due to protonation. Also, the reduced pH can potentially throw off the pH-sensitive enzymes in a particular type of bioassay (EMIT) often (but not always) used as the initial screening test, even for non-amine-containing drugs such as THC. Also, the effects of urine acidification on detection times (for any substance) are modest at best, often practically insignificant, and drinking vinegar is thus not very reliable as a standalone measure for beating a drug test.

High doses of niacin will help you pass

This legend has been around for at least a decade. Niacin, also known as Vitamin B3, is speciously claimed by some to "burn it out" of one's system when taken at high doses (250–500 mg per day). While some Internet (and other) sources often claim that it works wonders, there is no scientific evidence that it has any effect. Very high doses can also cause adverse side effects.

This legend may have been (inadvertently) inspired by Narconon, a Scientology-based drug rehabilitation program that uses exercise, saunas, and high doses of niacin (and other vitamins) to detox. It is also part of L. Ron Hubbard's general Purification Rundown, which can supposedly remove pollutants as well as drug residues. However, there are currently no peer-reviewed scientific studies to back these methods up.

Secondhand exposure will cause you to fail

This legend is technically true but highly misleading. According to a U.S. Army study, the amount of secondhand cannabis smoke needed to cause a false positive result (failure) is quite large indeed, and would require being sealed in an unventilated car or small room filled with marijuana smokers for several hours. Hair testing, however, is a different matter, particularly with passive exposure to crack/cocaine, which can deposit onto hair and be readily incorporated into it. Though for cannabis, typically only metabolites (produced by the body and thus not found in smoke) are tested rather than THC, so failure is unlikely to result from non-extreme passive exposure.

Ibuprofen causes false positives for THC

While this was true in the past, newer versions of the EMIT bioassay are much less sensitive to ibuprofen (Advil, Motrin, etc.), and this has become relatively uncommon as of 1998, at least in the United States. However, abnormally high doses of ibuprofen can still potentially cause a false positive in some cases. Nonetheless, this no longer works as an alibi for THC since GC/MS can now distinguish between the two.

Poppy seeds cause false positives for opiates

This rather humorous legend has been featured in several movies and television shows, such as Seinfeld, and contains a grain of truth. Poppy seeds do contain trace amounts of morphine, but it would require about 100 poppy seed bagels to reach enough to cause a positive (failed) test result. Poppy seed-filled pastries (such as hamantashen), on the other hand, do in fact contain enough to potentially cause a false positive.

An episode of MythBusters tested this legend out, and found that as little as three poppy-seed bagels was enough to cause a positive result for the remainder of the day they were eaten (though participants tested clean the following day). The results of this experiment are inconclusive, however, because a test was used with an opiate cutoff level of 300 ng/mL instead of the current SAMHSA recommended cutoff level used in the NIDA 5 test, which was raised from 300 ng/mL to 2,000 ng/mL in 1998 in order to avoid such false positives from poppy seeds. Nonetheless, as stated before, foods with a very high density of poppy seeds are best to be avoided as they can potentially cause one to cross even the higher threshold.

In addition, one thing poppy seeds do not do is serve as an alibi for heroin: a unique metabolite (6-monoacetylmorphine) is produced from heroin use that is never produced from consuming any other substance, let alone poppy seeds. Modern tests can thus readily tease out whether it was heroin or not, should someone try to claim they merely ate poppy seeds.

Cannabis remains detectable in urine for 30 days or more

While this is technically true in some cases, more recent studies have shown that detection times of 30+ days are actually quite exceptional, even for chronic users subjected to tests with lower than normal cutoffs. Under the typical 50 ng/mL cutoff for THC, an occasional or one-off user would be very unlikely to test positive beyond 3–4 days since the last use, and a chronic user would be unlikely to test positive much beyond 10 days. Using a more sensitive cutoff of 20 ng/mL (less common but still used by some labs), the most likely maximum times are 7 days and 21 days, respectively. However, one must remember that every individual is different, and detection times can vary due to metabolism or other factors.

See also

• Drug-Free Workplace Act of 1988
• Equine drug testing
• Forensic toxicology
• School district drug policies
• Urinalysis

External links

• US National Institute on Drug Abuse (NIDA) Website
• US Substance Abuse and Mental Health Services Administration (SAMHSA) Website
• The National Clearinghouse for Alcohol and Drug Information
• A Political History of White House Drug Policy
• European Workplace Drug Testing Society
• The Drug and Alcohol Testing Industry Association
• US Drug Testing Laws - Full text Version
• Substance Abuse
• Hair Vs. Urine - Drug Testing