ABSTRACT
Drugs of abuse are commonly encountered in the workplace and the occupational health specialist is often asked to perform and interpret tests to check for the presence of such substances. A clear understanding regarding the limitations of testing is required for this purpose as this field has many potential pitfalls. This is the first of two articles that provide a broad overview of the commonly encountered drugs of abuse (DOA); the biological samples that can be used; possible interferants and adulterants that may be encountered; and the role of the laboratory and pathologist. The second article in this series examines the technology involved; looking briefly at immunoassays and mass spectrometry; and issues regarding cut-points and interpretations