Which drugs are most frequently detected in workplace testing?

Lolita Tsanaclis

Lolita Tsanaclis

on Mar 10, 2021

Every employer has a duty of care to its employees. Part of this requires the development of a comprehensive occupational health and safety policy. This should not only include the protection from potential harm caused by equipment or the physical surroundings, but also any harm that could be inflicted by individual workers, either to themselves or to others.

Read our full guide to drug and alcohol testing in the workplace

That’s why it’s so important to have a solid workplace drug and alcohol policy in place, backed up by accurate and reliable drug and alcohol testing in the workplace.

We provide testing and analysis services for a number of organisations who are looking to reduce drug-related issues in the workplace, and help affected employees to get the support they need. This means we have a wealth of data on the drugs that are most frequently detected - here’s what those drugs are, the signs of misuse you should look out for, and the best ways to test for these substances.


With cannabis having been legalised in parts of the US and Canada, unsurprising is growing in the UK - particularly in workplaces, given that it is used for its purported stress and pain relieving properties.

What impact does cannabis have?

The effects of cannabis can vary depending on the person, on the strain, and on how much is taken. Common effects to look out for include an individual:

  • Talking or laughing more
  • Becoming happier or more relaxed
  • Feeling tired or drowsy
  • Feeling nauseous or faint
  • Having hunger pangs
  • Having mild hallucinations
  • Finding it more difficult to focus or remember things
  • Feeling paranoid, anxious or confused
  • Experiencing dilation of the pupils

Read our comprehensive guide to workplace drug testing programmes.


The use of both powder cocaine and crack cocaine is growing in the UK, as well as purity increasing and prices falling. This could explain why we are seeing a rise in workplace usage.

What impact does cocaine have?

The following signs can be indicators that someone is under the influence or addicted to cocaine:

  • High levels of energy and talkativeness
  • Constant nose running, sniffing or nose bleeds (or visible traces of white powder on/in the nostrils)
  • Sleep deprivation
  • Mood swings
  • Loss of appetite
  • Being late to work - or missing work
  • Depression or paranoia


During the first COVID-19 lockdown, the UK saw a decline in party drugs like MDMA. However, their use remains high - so high, in fact, that there are repeated calls for the government to legalise the selling of such drugs in pharmacies, to reduce organised crime and better manage the associated health risks.

What impact does MDMA have?

MDMA can vary hugely in its quality and purity, and can affect different people in different ways. However, common signs where an employee is using MDMA include:

  • Having high levels of energy or being very awake at strange times
  • Greater emotional warmth and increased friendliness
  • Being more empathetic than normal
  • Greater levels of self-esteem
  • Teeth grinding or jaw clenching
  • A distorted sense of time
  • Inability to focus or concentrate
  • Dilated pupils or rapid eye movement
  • Loss of inhibitions


After their growth in the US, prescription opiates like codeine and fentanyl have seen usage rise across the UK. For many, this will be down to an increasing addiction to prescription medication, leading to fears some may turn to the black market to satisfy their body’s demands for these substances.

To learn more about drug and alcohol testing, take a look at our e-learning page.

What impact do opiates have?

Signs that a worker could be misusing opiates include:

  • ‘Pinpoint’ constricted pupils
  • Itchy, flushed skin
  • “Borrowing” prescription medications from others
  • Sudden, dramatic mood swings
  • Risky behaviour or poor decision-making
  • Passing on activities they previously enjoyed
  • Changes in sleeping patterns

How do employers test for these substances?

Employers may do drug and alcohol testing for workplace substance misuse in a variety of different ways, depending on the situation an individual needs to be tested, the ease of conducting certain testing methods, and other factors.

Should a test be required to understand whether someone is under the influence of a substance at that specific time - in a random drug test, for example, or after an accident or other incident where drug use is suspected - then blood, urine or oral fluid testing can be used.

Blood testing is a highly accurate method of establishing whether an individual has used a substance in the few hours before the test, while urine can detect use in the few days before the test. Blood drug tests offer a very short window of detection, so are used when the subject is suspected to be under the influence of drugs or alcohol at the time of testing.

While drugs in urine can be detected for several days, oral fluid typically 5 to 48 hours - and in hair for several months - the timeframe is typically minutes to hours in the blood. As such, blood testing provides a snapshot of current usage only, and is often used at accident sites to establish whether those involved were under the influence at the time of the accident.

An oral fluid test can be taken with a simple swab.. And while urine testing is fast and non-invasive, the results can easily be tampered with.

For understanding longer term drug use trends, hair testing is our clients’ preferred approach. Often used for pre-employment testing or continual employee monitoring, hair testing is an incredibly accurate detection method near impossible to cheat. Sampling is non-invasive, and we are able to turn around results within just a few working days. Our tests can establish longer term patterns of drug use or non-use in individuals.

A workplace drug and alcohol policy is one way to fulfil your duty of care to your employees - demonstrating your commitment to protecting each individual within the organisation. While a workplace drug testing programme is a good way to monitor levels of substance misuse, it’s also important to understand some of the physical, behavioural and mental signs of drug use. The sooner suspicions about an individual’s drug use are confirmed or denied, the sooner they can receive the support they need. Early detection and intervention means it’s less likely there will be further problems in the workplace down the line.

Our e-learning resources give you even more insight into the world of drug and alcohol testing. Click here to find out more.

Image: Pixabay - no attribution needed

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Lolita Tsanaclis

Lolita Tsanaclis

Dr. Lolita Tsanaclis, Chief Scientific Officer of Cansford Laboratories Limited, has been developing methods for the analysis of drugs in hair since 1993. She has been involved in drug testing using hair, blood and oral fluid samples for medico-legal and workplace sectors for over three decades. Dr Tsanaclis is published extensively as author and as co-author in highly regarded peer-reviewed publications and scientific presentations.

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