Numerous literature and articles regarding the collection, processing, and analysis of drugs in oral fluid have been published. Many review papers have collated the published literature, and they pointed that the detection of drugs in oral fluid has been the subject of extensive research for many years. Saliva is basically noninvasive, accessible, rapidly collectable and processed with relatively straightforward procedures in the laboratory.
The main focus of this chapter is the proposed workplace drug classes, which have all been identified in saliva using a collection device or by spitting the saliva.
National Household Survey published research has showed that, participants preferred oral fluid for donation to hair and urine. Additionally, it was the one with the most compliance, fewest refusals, and the least problematic specimens (Figure 7-1).
Figure 7.1 Biological matrix selected for drug testing (n=627). Data from (8)
In 2003, Bennett et.al concluded that the urinalysis in detecting the opiates and methadone presence was accurate, and the absence of methadone and benzofdiazepines (9). As a matrix for workplace testing urine is widely used and accepted, but the oral fluid is getting popular due to the following reasons:
The ease of specimen collection, i.e it can be collected at the employment site, making it more possible for the individual to be not required to be present at a collection site for sample donation. (saving time and cost related preemployment drug testing)
No chance of substitution or adulteration, i.e the observed collection of samples can decrease the chances of any errors related to sample collection, this can be specially observed when the test matrix is urine sample.
Less time consuming, non-invasive, i.e the acquisition of sample is rapid, easy and most important non invasive, giving more willingness to the subject and the collector.
However, problems might occur in oral drug testing but they are rare and occasional, the most common being the “dry mouth syndrome” in which the subject is not able to produce an adequate amount of sample. Secondly the shorter length of time for which the drugs are detectable (as compared to urine) is the second main disadvantage. The people who are chronic users have increasingly sensitive technological developments and identification of metabolites of longer half-lives than the testing or parent drug in saliva; this may not be considered to be a problem.