Introduction
Oral fluid (mostly saliva) can be collected by placing a small absorbent pad in the mouth for a few minutes. Drugs which are present in the blood will partition into saliva and therefore analysis of this material is an alternative to urine testing.
The science of saliva testing is well founded as an alternative to urine testing and recent work has established saliva to be a worthy and complementary matrix.
Indeed saliva testing has certain advantages over urine testing and may well become the matrix of choice for certain types of testing where a close correlation between drug presence and impairment is desirable (eg. in 'for-cause' testing).
Advantages of Saliva Testing
- Saliva drug concentrations can be related to plasma free-drug concentrations, and hence to the pharmacological effects of drugs. The presence of drugs in saliva therefore is more likely to correlate with effect or impairment. Studies of drugged drivers have generally shown a high correlation between saliva drug levels and observed impairment.
- Saliva collection is non-invasive and is likely to be more acceptable than urine. Collection is easy and requires minimal facilities to carry it out. It is also faster.
- The sampling of saliva is always in sight of the collector; it is more difficult for a donor to adulterate the sample.
- Objective electronic measuring devices for screening saliva samples are now available.
- Saliva samples can be taken quickly following an incident. Toilet facilities are not necessary.
- Saliva testing is more likely to measure impairment at the time of sampling; therefore it may well be preferable as a testing basis under Information Commissioners Guidelines.
Oral Fluid Testing Systems and Devices
There are several devices marketed for the purpose of saliva collection, screening and analysis. The Cozart 'Rapiscan' system is of particular note.
The Cozart Rapiscan system incorporates the following features:
- Collection - the sample of saliva is collected using a device which is placed in the mouth. When sufficient sample has been collected, a blue indicator marks the end of the collection period (several minutes).
- Screening - the collected sample is screened on-site using an objective measuring instrument. A negative result is obtained within a few minutes and the donor is free to leave. Results are printed out on-site.
- Confirmation of suspected positives - If a positive screening test result is indicated, the sample can be divided into 2 portions and sent to the laboratory under chain-of-custody conditions for confirmation testing. This principle is similar to current urine testing procedures.
The Cozart Rapiscan system is fully portable and can be operated at virtually any location.
Service
NIVHA uses the Cozart Rapiscan system in those circumstances for which an instant indication for the presence of drugs is required, high correlation with impairment at the time of sampling and geographic flexibility is desirable. We can provide advice and guidance on the most appropriate detection method to use.
For companies which retain their own in-house occupational health staff we can supply the Rapiscan system, training services and procedure advice.