Blood, urine, oral fluid: Guidelines for selecting the biological matrix in drug and alcohol testing

In drug testing scenarios, achieving a balance among the pharmacokinetics of a drug, testing technology, and procedures is crucial to address the issue at hand accurately. Accurate information is essential both for responding appropriately to the situation and for substantiating any allegations. An individual’s status of substance use can be evaluated using blood, breath, and oral fluid samples. In contrast, urine tests can detect drug use from several hours to days, and hair tests can reflect drug use over several months. Each matrix has its advantages and disadvantages, which must be meticulously considered before selecting the most suitable one. This lecture will provide an overview of the fundamental principles of pharmacokinetics and physiology as they pertain to drug testing and the selection of the appropriate matrix.