|This article needs additional citations for verification. (June 2011)|
A drug test is a technical analysis of a biological specimen, for example urine, hair, blood, breath air, sweat, or oral fluid / saliva – to determine the presence or absence of specified parent drugs or their metabolites. Major applications of drug testing include detection of the presence of performance enhancing steroids in sport, employers screening for drugs prohibited by law (such as cannabis, cocaine and heroin) and police officers testing for the presence and concentration of alcohol (ethanol) in the blood commonly referred to as BAC (blood alcohol content). BAC tests are typically administered via a breathalyzer while urinalysis is used for the vast majority drug of testing in sports and the workplace.
The "12-panel urine screen" from Pinnacle BioLabs consists of 12 of the following:
- Amphetamines (including Methamphetamine)
- Cannabinoids (THC)
- Opioids (Codeine, Morphine, Heroin, Oxycodone, Hydrocodone, etc.)
- Phencyclidine (PCP)
- Synthetic cannabinoids (K2, Spice)
- Tricyclic antidepressants
- 1 Detection periods
- 2 Types
- 3 Methodologies
- 4 Legality, ethics and politics
- 5 Refusal
- 6 See also
- 7 References
- 8 External links
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. The graph depicts the longer detection times of the metabolites.
Oral fluid or saliva testing results for the most part mimic that of blood. The only exceptions are THC (tetrahyrocannabinol) and benzodiazepines. Oral fluid will likely detect THC from ingestion up to a maximum period of 6–12 hours. This continues to cause difficulty in oral fluid detection of THC and benzodiazepines.
Breath air for the most part mimics blood tests as well. Due to the very low levels of substances in the breath air, liquid chromatography - mass spectrometry has to be used to analyze the sample according to a recent publication wherein 12 analytes were investigated.
Rapid oral fluid products are not approved for use in workplace drug testing programs and are not FDA cleared. Using rapid oral fluid drug tests in the workplace is prohibited in only:
K2, also known as synthetic cannabinoids, is detectable for up to 3 days after single use or up to 30 days for chronic users. It wasn't tested for in the past but is now detectable in modern tests.
|Substance||Urine||Hair||Blood / Oral Fluid|
|Alcohol||6–24 hours Note: Alcohol tests may measure ethyl glucuronide, which can stay in urine for up to 80 hours||up to 2 days||12–24 hours|
|Amphetamines (except methamphetamine)||1 to 3 days||up to 90 days||12 hours|
|Methamphetamine||3 to 5 days||up to 90 days||1–3 days|
|MDMA (Ecstasy)||3 – 4 days||up to 90 days||3 – 4 days|
|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||Infrequent users: 7-10 Days; Heavy users: up to 30 days;||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. THC (found in marijuana) may only be detectable in saliva/oral fluid for 2–24 hours in most cases.|
|Cocaine||2 to 5 days (with exceptions for heavy users who can test positive up to 7–10 days, and individuals with certain kidney disorders)||up to 90 days||2 to 10 days|
|Codeine||2 to 3 days|
|Cotinine (a breakdown 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|
|Tricyclic antidepressants (TCA's)||7 to 10 days||Undetectable||Detectable but dose relationship not established|
|LSD||2–24 hours||up to 4 days||2 to 4 days|
|Methadone||7 to 10 days||up to 90 days||24 hours|
|Steroids||3 to 30 days|
|PCP||3 to 7 days for single use; up to 30 days in chronic users||up to 90 days||1 to 3 days|
Urine drug screen
Drug screens are reported as pass or fail, with urine reported invalid or adulterated.
When an employer requests a drug test from an employee, or a physician requests a drug test from a patient, the employee or patient is typically instructed to go to a collection site or their home. The urine sample goes through a specified 'chain of custody' to ensure that it is not tampered with or invalidated through lab or employee error. The patient or employee’s urine is collected at a remote location in a specially designed secure cup, sealed with tamper-resistant tape, and sent to a testing laboratory to be screened for drugs (typically the Substance Abuse and Mental Health Services Administration 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. If requested by the physician or employer, certain drugs are screened for individually; these are generally drugs part of a chemical class that are, for one of many reasons, considered more abuse-prone or of concern. For instance, oxycodone and diamorphine may be tested, both sedative analgesics. If such a test is not requested specifically, the more general test (in the preceding case, the test for opiates) will detect the drugs, but the employer or physician will not have the benefit of the identity of the drug.
Employment-related test results are relayed to a medical review office (MRO) 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 to determine if there is any legitimate reason—such as a medical treatment or prescription.
On-site instant drug testing is 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.
Hair analysis to detect drugs of abuse has been used by court systems in the United States, United Kingdom, Canada, and other countries worldwide. In the United States, hair testing has been accepted in court cases as forensic evidence following the Frye Rule, the Federal Rules of Evidence, and the Daubert Rule. As such, hair testing results are legally and scientifically recognized as admissible evidence.
Although some lower courts may have accepted hair test evidence, there is no controlling judicial ruling in either the federal or any state system declaring any type of hair test as reliable.
Hair testing is now recognised in both the UK and US judicial systems. There are guidelines for hair testing that have been published by the Society of Hair Testing (a private company in France) that specify the markers to be tested for and the cutoff concentrations that need to be tested. Drugs of abuse that can be detected include Cannabis, Cocaine, Amphetamines and drugs new to the UK such as Mephedrone.
In contrast to other drugs consumed, alcohol is 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 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).
Presumptive substance testing
Presumptive substance tests identify a suspicious substance, material or surface where traces of drugs are thought to be, instead of testing individuals through biological methods such as urine or hair testing. The test involves mixing the suspicious material with a chemical in order to trigger a color change to indicate if a drug is present. Most are now available over-the-counter, and do not require a lab to read results.
Benefits to this method include that the person who is suspected of drug use does not need to be confronted or aware of testing. Only a very small amount of material is needed to obtain results, and can be used to test powder, pills, capsules, crystals, or organic material. There is also the ability to detect illicit material when mixed with other non-illicit materials. The tests are used for general screening purposes, offering a generic result for the presence of a wide range of drugs, including Heroin, Crack Cocaine, Methamphetamines, Amphetamines, Ecstasy/MDMA, Methadone, Ketamine, PCP, PMA, DMT, MDPV, Mephadone, and may detect rapidly evolving synthetic designer drugs. Separate tests for Marijuana/Hashish are also available.
Saliva drug screen / Oral fluid-based drug screen
Saliva / oral fluid-based drug tests can generally detect use during the previous few days. Is better at detecting very recent use of a substance. THC may onthan 12.0 hours in some cases. On site drug tests are allowed per the Department of Labor.
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: 1-24h
A disadvantage of saliva based drug testing is that it is not approved by FDA or 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.
Sweat drug screen
Sweat patches are attached to the skin to collect sweat over a long period of time (up to 14 days). These are used by child protective services, parole departments, and other government institutions concerned with drug use over long periods, when urine testing is not practical. There are also surface drug tests that test for the metabolite of parent drug groups in the residue of drugs left in sweat.
Drug-testing a blood sample measures whether or not a drug or a metabolite is in the body at a particular time. These types of tests are considered to be the most accurate way of telling if a person is intoxicated. Blood drug tests are not used very often because they need specialized equipment and medically trained administrators.
Depending on how much marijuana was consumed, it can usually be detected in blood tests within six hours of consumption. After six hours has passed, the concentration of marijuana in the blood decreases significantly. It generally disappears completely within 30 days.
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 is particularly so in individual (rather than team) sports such as athletics and cycling.
Random drug testing
Can occur at anytime, usually when the investigator has reason to believe that a substance is possibly being abused by the subject by behavior or immediately after an employee-related accident occurs during work hours.
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 beyond just self-administered drugs. These tests can also be done post-mortem during an autopsy in cases where a death was not expected. The test is usually done within 96 h (4 days) after the desire for the test is realized. 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 amphetamines, benzodiazepines, cocaine, methadone, opiates, cannabis, barbiturates and tricyclic antidepressants. Results are given in 10–15 min.
Before testing samples, the tamper-evident seal is checked for integrity. If it appears to have been tampered with or damaged, the laboratory rejects the sample and does not test it.
Next, the sample must be made testable. Urine and oral fluid can be used "as is" for some tests, but other tests require the drugs to be extracted from urine. 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 and the sweat collection component is removed and soaked in a solvent to dissolve any drugs present.
Laboratory-based drug testing is done in two steps. The first step is the screening test, which is an immunoassay based test applied to all samples. The second step, known as the confirmation test, is usually undertaken by a laboratory using highly specific chromatographic techniques and 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 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 tested using a 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 precise but expensive. False positive samples from the screening test will almost always 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 who will normally interview the subject of the drug test.
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 and is considered the Gold Standard of drug testing. Urine based tests have been upheld in most courts for more than 30 years. However, urinalysis conducted by the Department of Defense has been challenged for reliability of testing the metabolite of cocaine. There are two associated metabolites of cocaine, benzoylecgonine (BZ) and ecgonine methyl ester (EME), the first (BZ) is created by the presence of cocaine in an aqeous solution with a pH greater than 7.0, while the second (EME) results from the actual human metabolic process. The presence of EME confirms actual ingestion of cocaine by a human being, while the presence of BZ is indicative only. BZ without EME is evidence of sample contamination, however, the US Department of Defense has chosen not to test for EME in its urinalysis program. Mike Tyson, in his autobiography, claimed to have bypassed the urine test with a fake penis with clean urine.
A number of different analyses (defined as the unknown substance being tested for) are available on Urine Drug Screens. Here is a complete list from Pinnacle BioLabs.
Spray drug testing
Spray (sweat) drug test kits are non-invasive. It is a simple process to collect the required specimen, no bathroom is needed, no laboratory is required for analysis, and the tests themselves are difficult to manipulate and relatively tamper-resistant. The detection window is long and can detect recent drug use within several hours.
There are also some disadvantages to spray or sweat testing. There is not much variety in these drug tests, only a limited number of drugs can be detected, prices tend to be higher, and inconclusive results can be produced by variations in sweat production rates in donors. They also have a relatively long specimen collection period and are more vulnerable to contamination than other common forms of testing.
Hair drug testing
Hair drug testing is a method that can detect drug use over a much longer period of time, and is often used for highly safety-critical positions where there is zero tolerance of illegal drug use. 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. 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 timeframe 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.
Legality, ethics and politics
The results of federally mandating drug testing were similar to the effects of simply extending to the trucking industry the right to perform drug tests, and it has been argued that the latter approach would have been as effective at lower cost.
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.
In consultation with 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. All defendants serving on federal probation or federal supervised release are required to submit to at least three drug tests. Failing a drug test can be construed as possession of a controlled substance, resulting in mandatory revocation and imprisonment.
There have been inconsistent evaluation results as to whether continued pretrial drug testing has beneficial effects.
Testing positive can lead to bail not being granted, or if bail has already been granted, to bail revocation or other sanctions. Arizona also adopted a law in 1987 authorizing mandatory drug testing of felony arrestees for the purpose of informing the pretrial release decision, and the District of Columbia has had a similar law since the 1970s. It has been argued that one of the problems with such testing is that there is often not enough time between the arrest and the bail decision to confirm positive results using GC/MS technology. It has also been argued that such testing potentially implicates the Fifth Amendment privilege against self-incrimination, the right to due process (including the prohibition against gathering evidence in a manner that shocks the conscience or constitutes outrageous government conduct), and the prohibition against unreasonable searches and seizures contained in the Fourth Amendment.
According to Henriksson, the anti-drug appeals of the Reagan administration "created an environment in which many employers felt compelled to implement drug testing programs because failure to do so might be perceived as condoning drug use. This fear was easily exploited by aggressive marketing and sales forces, who often overstated the value of testing and painted a bleak picture of the consequences of failing to use the drug testing product or service being offered." On March 10, 1986, the Commission on Organized Crime asked all U.S. companies to test employees for drug use. By 1987, nearly 25% of the Fortune 500 companies used drug tests.
According to an uncontrolled self-report study done by DATIA and Society for Human Resource Management in 2012 (sample of 6,000 randomly selected human resource professionals), human resource professionals reported the following results after implementing a drug testing program: 19% of companies reported a subjective increase in employee productivity, 16% reported a decrease in employee turnover (8% reported an increase), and unspecified percentages reported decreases in absenteeism and improvement of workers' compensation incidence rates.
According to US Chamber of Commerce 70% of all illicit drug users are employed. Some industries have high rates of employee drug use such as construction (12.8%), repair (11.1%), and hospitality (7.9-16.3%).
- In 2000, an Australian Mining Company South Blackwater Coal Ltd with 400 employees, imposed drug-testing procedures, and the trade unions advised their members to refuse to take the tests, partly because a positive result does not necessarily indicate present impairment; the workers were stood-down by the company without pay for a week.
- In 2003, sixteen members of the Chicago White Sox considered refusing to take a drug test, in hopes of making steroid testing mandatory.
- In 2006, Levy County, Florida volunteer librarians resigned en masse rather than take drug tests.
- In 2010, Iranian super heavyweight class weightlifters refused to submit to a drug test authorized by the Iran Weightlifting League.
- Drug-Free Workplace Act of 1988
- Equine drug testing
- Forensic toxicology
- Presumptive and confirmatory tests
- School district drug policies
- Cannabis drug tests
- "Drugs of Abuse Reference Guide," Pinnacle BioLabs, Retrieved online April 11, 2007.
- U.S. Department of Transportation: National Highway Traffic Safety Administration (DOT HS 810 704). Pilot Test of New Roadside Survey Methodology for Impaired Driving. January, 2007.
- Erowid Alcohol Vault : Drug Testing. Erowid.org. Retrieved on August 7, 2011.
- Erowid Amphetamine Vault : Drug Testing. Erowid.org. Retrieved on September 5, 2013.
- Erowid Methamphetamine Vault : Drug Testing. Erowid.org. Retrieved on September 5, 2013.
- Erowid Barbiturates Vault : Drug Testing. Erowid.org. Retrieved on August 7, 2011.
- Erowid Cannabis (Marijuana) Vault : Drug Testing. Erowid.org (2010-02-28). Retrieved on August 7, 2011.
- Marijuana Detection Time Shorter Than Previously Assumed. norml.org (2006-02-23). Retrieved on March 13, 2012.
- Erowid PCP Vault : Drug Testing. Erowid.org (2009-11-03). Retrieved on August 7, 2011.
- "Medical Review Officer Manual". Medical Review Officer Manual. SAMSHA Gov.
- Pascal Kintz (August 30, 2006). Analytical and practical aspects of drug testing in hair. CRC Press. pp. 305–. ISBN 978-0-8493-6450-1.
- . Touch-know.com. Retrieved on March 10, 2014.
- Working Partners for an Alcohol- and Drug-Free Workplace. Dol.gov. Retrieved on August 7, 2011.
- http://www.erowid.org/psychoactives/testing/testing_info1.shtml Drug Testing Basics
- "Drug Test". 2007.
- "Federal Court Drug-Testing Device Under Fire, PharmChem Sweat Patch May Be "Too Good"". January 5, 2001.
- WebMD --> Toxicology Tests Author: Jeannette Curtis. Primary Medical Reviewer: Kathleen Romito, MD – Family Medicine. Specialist Medical Reviewer: R. Steven Tharratt, MD, MPVM, FACP, FCCP – Pulmonology, Critical Care, Medical Toxicology. Last Updated: May 9, 2008
- Sixteen devices for the detection of drugs of abuse in urine MHRA Report No. MHRA 03078. Report Date: October 2003
- "Principles of Drug Testing Technology," Drug Tests Direct, Retrieved online Dec 07, 2012.
- Jim Barlow (November 2006). "A Little Dab Will Do It". LASNews (University of Illinois). Archived from the original on January 29, 2007. Retrieved November 29, 2006.
- Maume, Chris (November 29, 2013). "Books of the year 2013: Sport". The Independent (London).
- Hatala, John W. (June 2003). The Feasibility of Testing Hair for Illicit Drug Use in the United States Marine Corps. Monterey, California: Naval Postgraduate School. p. 2. Retrieved May 7, 2009.
- Mireille Jacobson (April 2003). "Drug Testing in the Trucking Industry: The Effect on Highway Safety". Journal of Law and Economics 46 (1): 131–156. doi:10.1086/345584.
- Independent Inquiry into Drug Testing at Work. "Drug testing in the workplace: Summary conclusions of the Independent Inquiry into Drug Testing at Work". Retrieved January 17, 2008.
- . National Treasury Employees Union v. von Raab. 86-1879, US Supreme Court, 1989.
- Skinner v. Railway Labor Executives Assoc. 87-15555. US Supreme Court, 1989
- Miller, NS; Giannini, AJ; Gold, MS; Philomena, JA (1990). "Drug testing: medical, legal, and ethical issues.". Journal of substance abuse treatment 7 (4): 239–44. doi:10.1016/0740-5472(90)90047-T. PMID 2290186.
- 18 U.S.C. § 3563, 18 U.S.C. § 3583
- Christy A. Visher. "Pretrial Drug Testing: Panacea or Pandora's Box?". Annals of the American Academy of Political and Social Science 521.
- Cathryn Jo Rosen; John S. Goldkamp (Spring 1989). "The Constitutionality of Drug Testing at the Bail Stage". The Journal of Criminal Law and Criminology (1973–) 80 (1): 114–176.
- Lennart E. Henriksson (June 1991). "The Unconvincing Case for Drug Testing". Canadian Public Policy / Analyse de Politiques 17 (2): 183–196. doi:10.2307/3551028. JSTOR 3551028.
- Deborah F. Crown; Joseph G. Rosse (Fall 1988). "A Critical Review of the Assumptions Underlying Drug Testing". Journal of Business and Psychology 3 (1): 22–41. doi:10.1007/BF01016746.
- "Employee Drug Testing Study". Global Drug Policy.
- "EAP Employee and Supervisor Drug Education". USUHS.mil.
- "Substance Abuse in the hospitality industry". Arkansas Small Business Development Center.
- Holland, Peter. "Case-Study. Drug Testing in the Australian Mining Industry". Surveillance and Society: 204–9.
- "White Sox Players Almost Refused Drug Test". Los Angeles Times. Associated Press. March 12, 2003.
- Voyles, Karen (October 6, 2006). "Library volunteers just say no to drug testing". Gainesville Sun.
- "Iranian weightlifters refuse drug testing". February 16, 2010
- US National Institute on Drug Abuse (NIDA) Website
- Humphreys K, Rappaport J (August 1993). "From the community mental health movement to the war on drugs. A study in the definition of social problems". Am Psychol 48 (8): 892–901. doi:10.1037/0003-066X.48.8.892. PMID 8379597. A Political History of White House Drug Policy
- US Substance Abuse and Mental Health Services Administration (SAMHSA) Website
- European Workplace Drug Testing Society
- The Drug and Alcohol Testing Industry Association
- National Institute on Drug Abuse