A drug test is an analysis of urine, hair, blood, sweat or saliva to test for the presence of drugs or alcohol. Drug testing is used to detect drugs in people who are employed by some employees to check for the presence of performance enhancing drugs in sport athletes or by the police in relation to law and order. Drug testing is highly controversial.
There are 5 main types of drug testing that are performed. These are urine, blood, hair, saliva and sweat tests. Urine testing, or urinalysis is the least expensive and the most commonly used test. This test can be performed on-site or the sample of urine is sealed by tamper-resistant tape and sent to a laboratory for testing. Urine testing can detect most drugs within set time period. Blood testing is more accurate but also more expensive and has a shorter period of detectability. Hair tests can accurately test for the presence of substances for the longest amount of time. Saliva is relatively easy to test but cannot test for all substances. Sweat is not as comprehensive but can determine the presence of substances for longer times than blood or saliva.
Drug testing typically will test for the following substances; alcohol, cannabis, amphetamines, cocaine, heroin and methamphetamines. Other drugs including barbiturates, anabolic steroids, various other performance enhancing drugs, and PCP.
The following chart shows detection periods for substances by test type. It should be noted that the ranges for the values are because each person has a different level of use, body mass, overall health, drug tolerance, pH levels and other variables.
| Substance | Blood | Saliva | Sweat | Urine | Hair |
| Alcohol | 12 hrs | 6-12 hrs | unknown | 6-24 hurs (5 days with EtG) | n/a |
| Amphetamine | 12 hrs | 3 days | unknown | 1-4 days | up to 90 days |
| Barbituates | unknown | unknown | unknown | 1-21 days | unknown |
| Benzodiazepines | unknown | unknown | unknown | 1-42 days | unknown |
| Cannabis (single use) | 2-3 days | 12-24 hrs | unknown | 2-3 days | up to 90 days |
| Cannabis (habitual use) | 2 weeks | 12-24 hrs | unknown | 15-30 days | up to 90 days |
| Cocaine | unknown | 1 day | unknown | 4-5 days | up to 90 days |
| Codeine/Morphine | unknown | 12-36 hrs | unknown | 2-4 days | up to 90 days |
| Heroin | unknown | unknown | unknown | 2-4 days | up to 90 days |
| Methamphetamine | 1-3 days | unknown | unknown | 3-5 days | up to 90 days |
| PCP | 1-3 days | 3 days | unknown | 3-7days | up to 90 days |
Roadside drug testing refers to on the spot drug testing for drivers of vehicles. Police and road authorities believe that driving while under the influence of drugs or alcohol is one of the major contributors to road accidents and deaths. The testing aims to deter individuals from both using drugs and driving under the influence.
Roadside drug testing is usually conducted in conjunction with alcohol testing. Roadside drug testing typically aims to find the presence of cannabis, opiates, amphetamines and MDMA. The test that is performed is an saliva test and if it comes back with a positive reading, the driver of the vehicle will have to provide a second sample. Drivers will be required to undertake a blood test if this second sample shows the presence of one of these drugs.
In many industries and workplaces, drug testing is used as part of routine checks for employment and random testing is part of continuing employment. Employers test employees for drugs to ensure the health and safety of the workplace, to ensure productivity levels are met and to deter employees from using illegal substances. Insurance benefits are also another reason that some employers may implement workplace drug testing.
Some workplaces allow employers to test staff if there has been an accident, if there is suspicion of drug use or if a staff member is returning to work. If the test is found to show that there are levels of illegal drugs present, the individual may have their job terminated on the spot and the person can be walked off the job. In some cases, employers may implement a process of counseling or mediation to resolve the issue.
Drug testing, however legal, has many critics. Issues have arisen around the invasion of privacy associated with drug testing. An example of this is the fact that a urine test can show the presence of not only drugs but other medical conditions and pregnancy. Employee rights advocates have continuously criticized the use of urine testing prior to employment as they have anecdotal evidence to show that the information in the urinalysis can be used as a way of discriminating against employment.
The validity of the tests has also come into question, especially in regards to errors between distinguishing between legal or prescription medications and illegal substances. Cold medications which contain psuedoephidrine or ephidrine can cause drug tests to show a false-positive result. Medications for other conditions such as depression, Parkinsons and ADHD also may produce positive results in a drug test. If this is the case, an individual can request a follow up test to ensure the test has located the correct substance and not incorrectly shown a positive for a legal drug.
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