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Why there’s a place for both narrow- and wide-window drug testing in the workplace

When it comes to workplace drug testing, the most common test methods are urine, oral fluid and hair. Urine and oral fluid (saliva) testing are ideal for on-site testing because they are quick, accurate and provide immediate results. As such, these tests are known as ‘narrow-window’ forms of testing: their period of detection is from 30 minutes up to a few days, although this can depend on the particular substance taken. Hair drug testing is particularly useful to gain a more comprehensive overview of a person’s drug use. It is known as a ‘wide window’ form of testing, which can determine a history of drug intake for 1 month (and up to 1 year if necessary).

Both types of test have a part to play in workplace testing. By using both narrow- and wide-window testing, employers can gain a much more detailed, accurate picture of long-term and short-term drug use.

Narrow-window testing

Narrow-window testing can help promote a culture of safety, responsibility and wellbeing in the workplace, especially in settings where safety is paramount. For example, those in high-risk occupations such as construction workers, drivers and workers operating potentially dangerous machinery, need to be alert and of sound mind. Any compromise in these faculties can have dire consequences.

AlphaBiolabs’ urine drug testing can test for 14 drugs and their metabolites: amphetamine, barbiturates, benzodiazepines, buprenorphine, cannabis, cocaine, ecstasy (MDMA), ketamine, methadone, methamphetamine, opiates, phencyclidine (PCP), propoxyphene and tramadol. Most drugs are flushed out of the body in a matter of days. Drugs including cocaine, MDMA and methamphetamine can be present in urine for roughly 3–5 days, but cannabis can stay in urine for as long as 28 days after chronic use.

The fully self-contained screening kit can be used by both men and women and has tamper protection features to help ensure integrity of the sample. For workplace testing on site, a dedicated toilet facility needs to be provided for the testing process.

Workplace sample collectors follow strict procedures to ensure that chain of custody is retained and that confidentiality remains throughout the whole testing process. This means that adulteration of samples is minimised by cisterns and taps being sealed. Individuals are also asked to empty their pockets and leave bags and belongings outside of the testing area.

Oral fluid testing is also ideal for workplace testing because it can easily be performed on site, quickly, without the need for dedicated collection facilities. It’s period of drug detection is from 30–60 minutes after ingestion up to 48 hours, although again this can depend on the particular substance taken. The entire test takes 20–30 minutes and involves placing an absorbent collector (similar to a large swab) inside an individual’s mouth for up to 2 minutes to soak up sufficient saliva. The sample is then instantly screened to establish whether any drugs are present.

Oral fluid testing is one of the most popular methods of for-cause (or post-incident) screening when there are reasonable grounds to suspect that there has been recent misuse of drugs in the workplace. It is able to test for amphetamine, benzodiazepines, cannabis, cocaine, ketamine, methadone, methamphetamine and opiates.

With both types of narrow-window testing, if the results are non-negative, the samples need to be sent to the lab for quantitative tests to determine exactly which drugs are present and in what quantity.

Wide-window testing

The advantage of hair drug testing is that drugs remain relatively stable in hair and can thus be stored indefinitely. This wide-window test can effectively confirm long-term exposure to drugs over a defined period depending on the length of hair collected (from 1 month up to 12 months – if sufficient hair is available).

After ingesting a drug, it is absorbed into the bloodstream. Drugs and their metabolites are then absorbed through the root of the hair and become embedded in the hair shaft. These metabolites remain in the hair as it grows, hence it is a suitable method for detecting a person’s historical drug intake on a month-by-month basis. Unlike urine and oral fluid tests, hair strand analysis cannot show recent drug history: it can take between 7–10 days for the hair containing the drug to grow above the scalp.

In many workplace scenarios, hair drug testing is used to support oral fluid and urine testing. It is particularly useful to gain a more comprehensive overview of a person’s drug use. Hair can be sectioned for segmented analysis, which is a month-by-month view of drug intake. Alternatively, an overview analysis can determine historic drug intake.

Drugs routinely tested for include amphetamine, benzodiazepines, buprenorphine, cannabis, cocaine, ecstasy (MDMA), ketamine, mephedrone, methadone, methamphetamine, opiates, phencyclidine (PCP) and zolpidem. Hair drug testing can also be arranged for GHB, LSD, spice, steroids, tramadol and other less common drugs.

Summary

Oral fluid testing

Advantages Disadvantages Workplace application
  • Narrow-window of detection: 30–60 minutes after ingestion up to 48 hours
  • On-site test with immediate results
  • Can ascertain recent drug use
  • Ideal for monitoring day-to-day usage
  • Ease of use
  • Low cost
  • Ideal for employers who need to carry out regular tests
  • Sample easy to collect: quick and non-invasive
  • Apparatus is compact, does not require electricity and can be used anywhere
  • Doesn’t require dedicated collection facilities
  • Hygienic
  • Small detection window
  • Easy to cheat (an employee could simply cut out drugs for a few weeks or even days prior to being tested – if scheduled)
  • Does not test for as many drugs as urine testing
  • More expensive than urine testing
  • Plays a vital role in random onsite testing
  • Perfect tool for checking drug usage in existing employees
  • Preferred method for for-cause (or post-incident) screening when there are reasonable grounds to suspect that there has been recent misuse of drugs in the workplace
  • Useful in high-risk industries where regular testing is necessary

Urine testing

Advantages Disadvantages Workplace application
  • Narrow window of detection: 3 days up to 28 days
  • On-site test with immediate results
  • Can ascertain recent drug use
  • Ideal for monitoring day-to-day usage
  • Ease of use
  • Low cost
  • Ideal for employers who need to carry out regular tests
  • Cheaper testing option than both oral fluid and hair testing
  • Tamper-prevention features prevent ‘fake’ samples
  • Small detection window
  • Needs dedicated toilet facilities for the collection
  • Could be tampered with if the sample collection is unsupervised or toilet facilities not prepared in advance
  • Donor may not be able to produce enough urine
  • Plays a vital role in random onsite testing
  • Perfect tool for checking drug usage in existing employees
  • Useful in high risk industries where regular testing is necessary

Hair testing

Advantages Disadvantages Workplace application
  • Wide window of detection: 1 month up to 1 year
  • Most accurate testing method for giving an overview of someone’s drug usage
  • Can determine historic drug intake
  • Most expensive Workplace testing method
  • Cannot determine recent drug use
  • Results are not immediate
  • Pre-employment testing to gain an understanding of someone’s drug history going back up to 12 months (depending on hair length)

Which is best?

By using both narrow- and wide-window testing, employers can gain a much more detailed, accurate picture of short-term and historic drug use. For example, an employee working in a high-risk industry, such as aviation, may have passed a pre-employment test when he or she joined the airline company, but a quick oral fluid test can give an instant answer as to any queries surrounding current usage. If the test is non-negative and confirmed in the laboratory, a hair drug test can then be done to establish whether or not there is a longer-term problem. Combining both narrow- and wide-window testing in this way provides a clearer picture and greater weight of evidence than simply using one or the other. The results of both recent and historic drug use can help employers decide on the best course of action, and may be needed as evidence in a tribunal or court hearing.

For information on how narrow- and wide-window testing can play a part in your workplace, contact AlphaBiolabs on 0333 600 1300, email info@alphabiolabs.com or visit our workplace testing services website at www.alphabiolabs.co.uk.

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Last reviewed: 05/10/2023

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