Abstract
The purpose of this study was to assess the concordance of self-reports of cannabis, cocaine and amphetamines, and the utility of these, with a saliva point of collection drug test, the DrugWipe 5+, in an emergency department (ED) setting. METHODS: A random sample of people admitted to either of two emergency departments at hospitals in British Columbia, Canada were asked to participate in an interview on their substance use and provide a saliva test for detection of drugs. ANALYSES: Concordance of self-reports and drug tests were calculated. Prior DrugWipe 5+ sensitivity and specificity estimates were compared against a gold standard of mass spectrometry and chromatography (MS/GC). This was used as a basis to assess the truthfulness of self-reports for each drug. RESULTS: Of the 1584 patients approached 1190 agreed to participate, a response rate of 75.1%. For cannabis, among those who acknowledged use only 21.1% had a positive test and 2.1% of those who reported no use had a positive test. For cocaine and amphetamines respectively, 50.0% and 57.1% tested positive among those reporting use, while 2.1% and 1.3%, respectively reported no use and tested positive. Self-reports of cannabis and amphetamines use appear more truthful than self-reports of cocaine use.