Is drug testing at work effective?

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 and there is also increased usage in the construction industry. The presence of drugs can be detected in urine, 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.

Testing has become more accurate and, if a sample is conducted by an approved laboratory and the sample is subject to a confirmation test. 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 are as follows:

• Only use drug or alcohol testing where it is needed to evidence impairment to work
• Use the least intrusive forms of testing practicable
• Tell workers what drugs they are being tested for
• Base any testing on reliable scientific evidence of the effect on workers.

Drug testing is a costly and time-consuming process so 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.