Drug Testing

A drug test is a process using some kind of biological matter taken from an individual to determine previous drug use. Drug testing is a subject of much controversy. Many have argued that it is an invasion of privacy. The 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.

Types of Drug Testing

Drug tests can be divided into two general groups. The first type of testing involves the donor giving a sample of some bodily fluid or hair to an employer, doctor, law enforcement official, or a medical testing center. This is normally a sample of urine, blood, hair, or saliva/ oral fluid. After collection from the donor, the 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 a particular demographic group. The disadvantages are typically costs associated with the need for collection sites (urine, blood), and the delay in receiving results (up to 4 days.)

The second type of drug test is an on-site (workplace, school, washroom, or at-home) drug test that does 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.

Detection periods

The following chart gives approximate detection periods for each substance by test type. The ranges depend 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 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 exception is THC. Oral fluid will likely detect THC from ingestion up to a maximum period of 18-24 hours. NOTE 2: Urine can not detect current drug use. It takes approximately 6-8 hrs. post-consumption for drug to be metabolized and excreted in urine. Similarly, hair requires two weeks, and sweat, seven days.

 Types of Drug Testing

Urine drug screen
Also known as urinalysis, this procedure requires that one provide a sample of urine. Either a test card is used on site for immediate results (see "General" section), or the sample is sent away to a lab to undergo gas chromatography/mass spectrometry (also known as GCMS), 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 and/or drug-free urine and a wide range of adulterants on the internet.

Hair drug screen
Hair testing is quite accurate and can go back 6 months or longer, showing any controlled substances used in a sort of timeline. 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, however, 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 rate of growth 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. Additionally, for pre-employment hair testing, the inability to obtain a sample may be grounds for not hiring the individual.

Blood drug screen
Blood testing is usually performed by employers or insurance companies, usually after some kind of accident, such as one in the workplace. Blood is preferable in this case because the degree of intoxication can be approximated based on the amount of substance in the blood. For this reason, blood is the preferable fluid in emergency room situations where a drug overdose is suspected. In addition, by comparing the ratio of metabolites to the parent drug, the time of drug use can be estimated. This type of test is helpful to employers when there is a workplace accident because judges and juries are unlikely to award damages if it can be proven that that a person was impaired at the time of the accident. Blood may contain pathogens and must be treated as a biohazard by the lab, and as such must be disposed of in a specific manner (by contrast, urine is considered sterile, and the excess may be poured down the sink after testing). For this and other reasons, this test is expensive to administer, and is not commonly used.

Saliva drug screen / Oral fluid-based drug screen
Saliva / oral fluid-based drug tests can generally detect use during the previous few months. 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. The Victorian Police in Australia are also using random saliva-tests to detect drivers under the influence of amphetamines and cannabis.

Sweat drug screen
Sweat tests are patches attached to the skin to collect sweat over a long period of time (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, 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. 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 that drug. This type of testing has fallen out of favor with government agencies due to documented problems with certain drugs.