Bioanalytical procedures for determination of drugs of abuse in oral fluid
Recent advances in analytical techniques have enabled the detection of drugs and drug metabolites in oral fluid specimens. Although GC–MS is still commonly used in practice, many laboratories have developed and successfully validated methods for LC–MS(–MS) that can detect a large number of compounds in the limited sample volume available. In addition, several enzyme immunoassays have been commercialized for the detection of drugs of abuse in oral fluid samples, enabling the fast screening and selection of presumably positive samples. A number of concerns are discussed, such as the variability in the volume of sample collected and its implications in terms of quantitative measurements, and the drug recoveries of the many different specimen collection systems on the market. Additional considerations that also receive attention are the importance of providing complete validation data with respect to analyte stability, matrix effect, and the choice of collection method.