An automated assay for salivary amylase: A validity marker for oral fluid.

Oral fluid is a matrix well suited to use in teletherapy. However, in cases where direct observation is not possible, validity of the specimen is in question. We have adapted a commercial salivary amylase assay for use with the Quantisal™ oral fluid collection system. We have demonstrated acceptable analytical performance and determined a cutoff to distinguish valid from invalid oral fluid specimens. We determined that washing a donor's mouth with water was unlikely to a produce a falsely invalid result if the normal 10 min passes between drinking or eating and oral fluid collection. We conclude that the measurement of salivary amylase is useful for the determination of oral fluid specimen validity in cases where direct observation of the specimen collection is not possible. This feature would be most important in a teletherapy setting, which often does not include a video component. This study describes how an assay for salivary amylase may be used to establish possible substitution. This assay does not rule out adulteration.