ORAL FLUID Drug Testing

The scientific basis for use of oral fluid as an alternative specimen for drug testing has been broadly established. Corresponding developments have proceeded in analytical technologies that provide the needed sensitivity and accuracy for testing oral fluid specimens. Oral fluid and urine test results have been shown to be substantially similar, and oral fluid may have some inherent advantages as a drug test specimen. Oral fluid collection occur under observation, which should substantially lessen the risk of specimen substitution and adulteration and, unlike direct observed urine collections, the collector need not be the same gender as the donor. The parent drug is generally found in higher concentrations in oral fluids than are drug metabolites.

Use of commercial adulterants or mouthwashes were not found to interfere with the immunoassay or they did not affect test results if the products are used more than 30 minutes before specimen collection. The window of detection for oral fluid is narrower than it is for urine, and drug concentrations are generally lower. In general, drug testing of oral fluids detects drug use during the previous 24–48 hours, regardless of the route of administration, although the selection of cut-offs plays an important role in the length of the detection window.

Two basic types of collection devices currently exist: One is designed to collect undiluted (neat) oral fluid by expectoration; the second type makes use of an absorbent pad that is inserted into the oral cavity for specimen collection and then placed in a tube containing a diluent. All these collection devices maintain the integrity of the specimen during collection, storage and transport to the laboratory for testing. An indicator in the device demonstrates the adequacy of the volume of collected specimen; have a sealable, non-leaking container; and have components that ensure pre-analytical drug and drug metabolite stability; and the device components must not substantially affect the composition of drugs and drug metabolites in the oral fluid specimen.

Source: SAMHSA (Substance Abuse and Mental Health Services Administration)

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