Over 200 types of products have been approved by the U.S. Food and Drug Administration to test for drug use, according to the Department of Health and Human Services. These tests vary in the methods they use, what drugs the tests can detect and the amount of time it takes to get the results.
Significance
Drug tests are used for a variety of reasons. Employers often request a drug screening prior to offering a position to a job candidate, and drug tests may also be used during custody disputes, to detect the use of performance-enhancing substances by athletes and as part of court judgments. When used correctly, drug tests are highly accurate.
Common Types
The saliva test is popular in the workplace because it's non-invasive and quick. Testing and results usually take about 5 minutes. The test taker swabs the inside of the mouth with a bristle brush. This swab is then placed in a vial and results are available within minutes. There are limitations, however, as the test can only detect recent drug use of the most commonly used drugs, and false positives are possible.
Urine tests are highly accurate. Urine is placed in a collection cup and tested on site; results are sometimes available immediately. One difficulty with this form of testing is the need for the test taker to go to a lab. Also, lab workers are often faced with attempts to cheat the test, which could skew results.
Less Common Types
Other types of tests are used less frequently. Sweat testing requires the test taker to wear a bandage-type patch for up to 14 days to collect the sweat, according to the Drug Policy Alliance. The patch is sent to a lab for analysis at the end of the designated period. This patch can only detect drug use during the period the patch was worn. The results are considered to be questionable, and there is a higher rate of false positives compared to other types.
Hair testing is considered to be one of the most accurate drug tests. According to the Department of Health and Human Services, "Hair testing holds the potential to evaluate drug use over past weeks to months, instead of hours or days." Although this test is not generally affected by hair treatments, different types of hair react differently to the test; and if the test taker is bald or shaves off his head hair, body hair can be used for the same result.
Blood tests are considered to be intrusive and expensive. Although it is considered to be the most accurate drug test, it is used less often for these reasons.
Tested Drugs
Most drug tests test for the most commonly used drugs. The Substance Abuse and Mental Health Administration recommends testing for the five most commonly abused drugs, including cannabinoids such as marijuana, cocaine, amphetamines, opiates -- including heroin, codeine and morphine -- and phencyclidine, or PCP. An expanded test may also test for prescription drugs such as Vicodin and Xanax, as well as ecstasy, or MDMA, and alcohol.
At-Home Kits
At-home drug testing kits are available at many drug stores. Home test kits are considered to be accurate and easy to use, and are often marketed towards parents of teens. "U.S. News and World Report" notes that the limitations of these tests include the ease of cheating and the misleading results caused by false positives. The magazine also states that parents may miss an opportunity to help their children since these tests do not test for all commonly used drugs, including inhalants.
References
- Substance Abuse and Mental Health Services Administration: Workplace Resource Center
- "U.S. News and World Report": Seven Reasons Parents Should Not Test Kids for Drug Use
- Department of Health and Human Services: Testimony on Federal Workplace Drug-Testing
- Drug Testing Facts: Test Standards and Accuracy
- National Institute on Drug Abuse: Drug Testing
