Oral fluid and hair in workplace drug testing programs: new technology for immunoassays.

Workplace drug testing programs have embraced both oral fluid and hair as testing matrices. Saliva is popular due to its easy, rapid collection; its non-invasiveness compared to urine or blood; the convenience of collecting a specimen anywhere, anytime; and the difficulty of adulteration. The main advantage of saliva, however, remains its suitability for post-accident or 'for-cause' testing since the presence of a parent drug can assist in the determination of an individual being 'under the influence' of a drug. Hair, on the other hand, is useful for workplace programs, since its ability to provide historical information on drug intake ensures it is an excellent specimen for pre-employment testing. Both technologies have enjoyed collection and laboratory improvements for immunoassay screening over the last few years, and these are discussed in this perspective.