Interpreting Drugs of Abuse Results

The final results for drugs of abuse testing are in the form of a positive or negative answer based on drug cut-off levels. These levels are usually detailed in the company Alcohol and Other Drugs Policy or can be based on the Australian Standard 4308.
Although the amount of drug in the urine can be measured, there is no reliable correlation between this amount and the extent of cognitive or motor impairment in the individual.  Therefore a positive drugs of abuse test only indicates that the individual has used the drug previously.
Interpreting a positive drug test often requires a detailed knowledge of the properties of the drug and the limitations of the testing procedures.  Many medical or occupational health and safety staff will become proficient at this task for routine results, but backup by expert pharmacologists in the laboratory is absolutely essential for difficult cases.  Our expert pharmacologists are able to advise if an individual has re-used since the previous sample was collected and can back up the results with expert court evidence if a dispute arises.
When used in the occupational health and safety context, drug and alcohol testing should not be used in isolation.  It is only an effective tool when combined with education for all employees and counselling for those employees who test positive.
Page last updated: 14 Aug 2020