Is drug testing at work effective?

Despite claims from drugs-testing companies, there is no real evidence that drug-testing is common-place in British workplaces. It is mainly used in safety critical areas such as transport and energy generation or after an incident. There is also increased usage in the construction industry.

The presence of drugs can be detected in urine, for most drugs, for up to three or four days after use, although in the case of some drugs they can be detected for up to 30 days, especially after heavy use.

In the past, drug-testing was very unreliable. In recent years, testing has become more accurate and, if a sample is conducted by an approved laboratory and the sample is subject to a confirmation test, false positive results are now less common. Even when it does identify drug use correctly, what the test shows is simply whether the residues of a drug are present. It cannot tell with any certainty when the person took the drug, or whether they were under the influence of the drug.

Good practice recommendations say:

• Only use drug or alcohol testing where it provides significantly better evidence of impairment than other less intrusive means.
• Use the least intrusive forms of testing practicable to deliver the benefits to the business that the testing is intended to bring.
• Tell workers what drugs they are being tested for.
• Base any testing on reliable scientific evidence of the effect of particular substances on workers.
Drug testing is a costly and time-consuming process that is often used by organisations as a substitute for an effective drugs and alcohol policy. If an employer does introduce a testing programme it should ensure that:
• It is done by a laboratory accredited by the UK Accreditation Service.
• It is part of an effective and agreed workplace drug and alcohol policy which aims at supporting any person with a drug or alcohol problem.
• It is only done after impairment testing has been carried out and there is evidence that the person may be impaired as a result of drugs.
• No samples are taken without the informed consent of the person (this cannot be given under duress).
• There is an appeals process, with right to union representation, if anyone tests positive.