Drug Testing in the Workplace

Posted in : HR Updates on 13 February 2013
Helen O'Brien
Personnel and Training Services
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Helen O'Brien writes:

Testing employees for drugs is being considered by an increasing number of employers as they become more prevalent in the workplace. In the United Kingdom, between 200,000 and 300,000 tests are carried out each year, mainly in safety critical industries such as the transport sector.

In general drug tests are divided into two groups:

  1. Laboratory testing - The donor gives a sample of urine, blood, hair or saliva/oral fluid. After collection, the sample in a tamper-evident seal/integrity container is sent for laboratory analysis. The advantages of this type of test are accuracy, legal defensibility, and the ability to customise tests for a particular demographic group. The disadvantages are typically the costs associated with the need for collection sites (urine, blood), the costs of the analysis and the delay in receiving results (up to five days).
  2. On-the spot, on-site screening - This form of screening uses an inexpensive kit, which provides results within minutes. Samples should be collected under supervised conditions that respect human dignity. They should be collected under a chain of custody, i.e. in a tamper-proof sealed container in the employee’s presence and handled and stored carefully, so that the test results can be fully relied upon in court. Any positive results from on-site screening should be confirmed by a technique that identifies the specific drug, usually gas chromatography/mass spectrometry. Two identical samples should be taken either on-site or split in the test laboratory and the second sample kept for further analysis as part of any appeal by the employee.

The Law on Testing for Drugs at Work

Drug alcohol testing is highly controversial and raises issues of privacy and human rights. Employees cannot be forced to take drug tests unless it is a condition of their employment and is set out in their contract of employment, or the employee has given their consent in advance. Obtaining samples without consent could constitute the criminal offences of assault or battery. Employers who carry out unnecessary tests could be open to legal challenge.

Testing in Safety Critical Industries 

Provisions included in health and safety legislation, together with transport legislation, may lead employers in safety-critical industries to drug test. Drug testing is carried out on employees carrying out jobs in which impairment due to drugs could have disastrous effects for the individual, colleagues, members of the public and the environment.

Random Testing

Drug testing should only be introduced following proper consultation with staff and their representatives and should be even-handed. The employer needs to demonstrate that testing for drugs is necessary to combat a risk(s) and is limited to those employees that need to be tested to deal with the risk. The employer must obtain informed consent from the employee before carrying out a drug test.

Data Protection of Drug Testing Results

Information about an employee's health, which includes the results of drug testing, is sensitive personal data. Employers must, therefore, ensure they adhere to strict guidelines. The results of a drug test must remain confidential, even if the test is failed.


If an employee fails a drug test, their employer may be able to dismiss them summarily for gross misconduct, particularly if they work in a safety-critical profession and their drug use has noticeably impacted their job performance. However, the employer should always ensure that it follows the LRA Code of Practice on Disciplinary and Grievance Procedures, together with any of its own policies and procedures, before taking a decision to dismiss.


Companies that are concerned about drugs in the workplace should have a drugs policy which contains a clear outline of the aims and purposes of the policy and sets out the rules and procedures around drug use. The policy on testing should:

  • outline who is covered by the policy and whether a particular group (e.g., employees carrying out safety-critical work) is subject to tighter restrictions
  • outline what constitutes misuse
  • outline the testing procedure and why the test is necessary
  • outline what happens if a test proves positive and the disciplinary action that may be taken

The policy should be developed in full consultation with staff and union representatives.

This article is correct at 04/11/2015

The information in this article is provided as part of Legal-Island's Employment Law Hub. We regret we are not able to respond to requests for specific legal or HR queries and recommend that professional advice is obtained before relying on information supplied anywhere within this article.

Helen O'Brien
Personnel and Training Services

The main content of this article was provided by Helen O'Brien. Contact telephone number is 028 2564 4110 or email HelenOB@pts-ni.com

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