What's the agreement between self-reported and biochemical verification of drug use? A look at permanent supportive housing residents.

Self-reported substance use is commonly used as an outcome measure in treatment research. We evaluated the validity of self-reported drug use in a sample of 334 adults with mental health problems who were residing in supportive housing programs. The primary analysis was the calculation of the positive predictive values (PPVs) of self-report compared to an oral fluid test taken at the same time. A sensitivity analysis compared the positive predictive values of two self-reported drug use histories: biological testing window (ranging between the past 96h to 30days depending on drug type) or the full past 90-day comparison window (maximum length recorded during interview). A multivariable logistic regression was used to predict discordance between self-report and the drug test for users. Self-reported drug use and oral fluid drug tests were compared to determine the positive predictive value for amphetamines/methamphetamines/PCP (47.1% agreement), cocaine (43.8% agreement), and marijuana (69.7% agreement) drug tests. Participants who misreported their drug use were more likely to be older, non-White, have no medical insurance, and not report any alcohol use. In general, amphetamine/methamphetamine/PCP and cocaine use was adequately captured by the biological test, while marijuana use was best captured by a combination of self-report and biological data. Using the full past 90day comparison window resulted in higher concordance with the oral fluid drug test, indicating that self-reported drug use in the past 90days may be a proxy for drug use within the biological testing window. Self-report has some disadvantages when used as the sole measure of drug use in this population.

Using environmental forensic microscopy in exposure science.

Environmental forensic microscopy investigations are based on the methods and procedures developed in the fields of criminal forensics, industrial hygiene and environmental monitoring. Using a variety of microscopes and techniques, the environmental forensic scientist attempts to reconstruct the sources and the extent of exposure based on the physical evidence left behind after particles are exchanged between an individual and the environments he or she passes through. This article describes how environmental forensic microscopy uses procedures developed for environmental monitoring, criminal forensics and industrial hygiene investigations. It provides key references to the interdisciplinary approach used in microscopic investigations. Case studies dealing with lead, asbestos, glass fibers and other particulate contaminants are used to illustrate how environmental forensic microscopy can be very useful in the initial stages of a variety of environmental exposure characterization efforts to eliminate some agents of concern and to narrow the field of possible sources of exposure.