The use of oral fluid (saliva) as a biological specimen for the detection of drugs of abuse is growing in popularity within the workplace. The increased popularity of oral fluid drug testing is due to inherent advantages over the standard urine drug test. Oral fluid specimen collection using is simple and non-invasive. Collection can occur at any time or location without embarrassment to the donor.

The specimen can be collected from the donor under direct observation, thus minimizing the potential for specimen tampering and/or adulteration. Oral fluid drug concentrations can be related to plasma free-drug concentrations and the pharmacological effects of drugs. As a result, oral fluid drug concentrations can provide information similar to that provided by plasma or blood drug concentrations.

Consideration should be given to the effect that some drugs or medical conditions have on the donor's ability to secrete oral fluid. As a result, oral fluid may not be available from all individuals at all times. 

Oral fluid testing can test for the following classes of drugs: