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Drug test is a process using some kind of biological matter taken from an individual to determine drug use. It is a matter of much controversy - many have argued that it is an invasion of privacy.

Moreover, accuracy and effectiveness of some tests are also in question. However, if proper steps are followed, including a GC/MS quantitative laboratory confirmation test, drug testing technology is highly reliable.

General information about drug tests


Drug tests can be divided into two general groups, where the first group is the kind most people are familiar with. This type of testing involves the donor giving a sample of some bodily fluid or hair to an employer, doctor, law enforcement official, or sometimes medical testing center. This is usually a sample of urine, blood, hair, or saliva. After collection from the donor, that sample is sealed with a tamper-evident seal and sent to a laboratory for analysis. The primary advantages of this type of test are accuracy, legal defensibility, and the ability to customize tests for particular demographic group. The disadvantages are typically costs associated with the need for collection sites, and the delay in receiving results which is up to 7 days.

The second type of drug test is an on-site, for example workplace, school, washroom, or at-home. These are drug test that do not require a laboratory. These types of tests provide the advantages of lower cost and availability of results within minutes. Furthermore, if on-site tests, such as oral fluid-based or saliva tests are used, the problem of beating the tests, otherwise known as sample adulteration or substitution, can be virtually eliminated. On-site tests provide qualitative results, and when supplemented with laboratory-based confirmation tests, can be defended in a court of law as well.

Drug testing in the United States basically began in the late 1980s. It started with the testing of certain federal employees and specific occupations. Drug testing guidelines and processes, in these areas exclusively, are established and regulated, and require that companies that use professional drivers, specified safety sensitive transportation, or oil- and gas-related occupations, and certain federal employers, test them for presence of certain drugs. These test classes were established decades ago, and include five specific drug groups, but they do not account for current drug usage patterns. For example, the tests do not include synthetic opiates, such as oxycodone, oxymorphone, hydrocodone, or hydromorphone, compounds that are highly abused in America. However, there are many other drug testing labs and on-site tests that offer a wider or more appropriate set of drug screens, more reflective of current drug abuse patterns. As noted above, these tests include synthetic pain killers such as Oxycodone, Oxymorphone, Hydrocodone, Hydromorphone, benzodiazepines or Valium, Xanax, Klonopin, Restoril, and barbiturates in other drug panels. The confirmation test can tell the difference between methamphetamine and ecstasy, and in the absence of detectable amounts of methamphetamine in the sample, the lab will either report the sample as negative or report it as positive. Gamma-hydroxy-butyrate was not routinely tested for in the early 1990s, but due to increasing use, some labs have added it as an optional test although GHB is rare in pre-employment screening. However, it is commonly checked for in suspected cases of drug overdose, date rape, and post-mortem toxicology tests. Ketamine may or may not be tested for, depending upon the preferences of the entity paying for the test, though testing for it is uncommon. In general, the greater the number of drugs tested for, the higher the price of the test, so many employers stick to the NIDA 5 because of financial reasons.

Other drugs, such as meperidine, fentanyl, propoxyphene, and methadone are not commonly tested for in most pre-employment situations, but these drugs are more likely to be included in tests for certain demographic groups. These groups are healthcare workers, drug rehab patients, and similar. Hallucinogens other than cannabis and PCP, such as mushrooms, LSD, and peyote, are rarely tested for.

Detection periods of drug tests

The ranges of detection period depends on 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 drug. For example, heroin and cocaine can only be detected for a few hours after use. However, 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. Furthermore, oral fluid or saliva testing results for the most part mimic that of blood. The only exception is THC because oral fluid will likely detect THC from ingestion up to a maximum period of 18-24 hours. What’s interesting is that urine can not be used to detect current drug use since it takes approximately 6-8 hours post-consumption for the drug to be metabolized and excreted in urine. Similarly, hair requires two weeks, and sweat even seven days.

Common types of drug tests

Urine drug screen, also known as urinalysis, is a procedure that requires that one provide a sample of urine. Either a test card is used on site for immediate results, or the sample is sent away to a lab to undergo gas chromatography or mass spectrometry, also known as GCMS. It is known as high-performance liquid chromatography or immunoassay analysis. Sample substitution or adulteration have become a significant issue in the United States, due to the prevalence of synthetic or drug-free urine and a wide range of adulterants on the internet. Some people attempt to beat a urine test by drinking copious amounts of water. However, a sufficiently diluted sample may be rejected due to its clear color. Too clear samples may be flagged and tested for specific gravity but if the sample fails the specific gravity test, the sample is rejected and the dilution is reported to the entity that ordered the test.

Some diuretics and herbal extracts, such as goldenseal, are marketed as a quick detox from controlled substances. However, their efficacy is questionable. Some types of urinalysis can even detect the use of these detox products. One of the methods to test for adulterants is to add some amount of an actual drug to a small portion of the sample and then retest that portion, so if a masking agent is present in the urine, the resulting drug test will have a negative result despite the fact that a drug was added. This situation is also usually reported to whomever ordered the drug test. 

Hair drug screen testing is quite accurate and can go back 6 months or longer. It shows any controlled substances used in this timeframe. As hair grows out, any drugs used are encased in the hair shaft, so the longer the hair, the longer back in the individual’s drug history the lab can detect. Most legitimate testing facilities only use hair within about 3-5 cm of the scalp, and discard the rest. This limits the detection history to about 90 days, depending upon the growth rate of the individual’s hair. Some people attempt to circumvent this through shaving their heads. In the absence of the required amount of hair on the scalp, body hair can be used as an acceptable substitute to get the results. Additionally, for pre-employment hair testing, the inability to obtain a sample may be grounds for not hiring the individual suspect of drug abuse.


Saliva drug screen and oral fluid-based drug screen - 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 can not be adulterated. 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. Oral fluid-based tests are as accurate as urine and can be obtained from quality suppliers in the United States. 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 in the blood.

Sweat drug screen are patches attached to the skin to collect sweat over a period of time, most commonly 10-14 days. These are almost exclusively used by child protective services, parole departments, and other government institutions concerned with drug use over long periods, especially when urine testing is not practical. The patches have security features that keep them from being covertly removed and then reapplied without the knowledge of the testing agency, and at the end of the test period, the patch is removed by a social worker or parole officer and sent to a lab for analysis. If the person has used any drugs during the period that the patch was in place, they will test positive for the drug. This type of testing has fallen out of favor with government agencies due to documented problems with some drugs.