In Practice

Cannabis legalisation and testing for cannabis use in safety- and risk-sensitive environments

J B Laurens, P A Carstens


The legalisation of cannabis by the High Court of South Africa, which was confirmed by the Constitutional Court, imposes challenges to occupational medical practitioners acting as medical review officers in compliance testing and fit-for-service medical examinations. The lipophilic character of the psychoactive component of cannabis, delta-9-tetrahydrocannabinol (Δ9-THC), and its prolonged elimination half-life, create challenges for the ethically and scientifically correct management of the legal use of cannabis in risk-sensitive environments. Important issues to consider in testing for cannabis use are: the stance of ‘zero tolerance’; screening and confirmation cut-off concentrations; and the bio-matrices used for testing. Constitutional rights relate to privacy, freedom, autonomy, freedom of religion and the equal enjoyment of rights and privileges, which must be balanced against the health and safety of others.

Authors' affiliations

J B Laurens, Forensic Toxicology Laboratory, Department of Chemistry, Faculty of Agriculture and Natural Sciences, University of Pretoria, South Africa

P A Carstens, Centre for Law and Medicine, Department of Public Law, Faculty of Law, University of Pretoria, South Africa

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Cannabis; Cannabis use; Workplace; Testing; Drug testing; Cannabis legislation; Prohibited substances; Drugs

Cite this article

South African Medical Journal 2020;110(10):995-998. DOI:10.7196/SAMJ.2020.v110i10.14615

Article History

Date submitted: 2020-09-30
Date published: 2020-09-30

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