Originally Posted by JJ Gold

http://www.erowid.org/psychoactives/...ng_info1.shtml

Saliva Tests

* Are a little more expensive than urine testing, but less than hair or blood. (~$15-$75).
* Are considered a relatively unintrusive method of drug testing.
* Are becoming more common.
* Are easy to administer but require lab processing to ensure accuracy.
* Detect use primarily within the past few days.
* Can detect more recent use than other testing methods.
* Have no nationally accepted standards or cutoff concentrations for detection, making results greatly dependent on the specific product purchased. This could also make results less-reliable and/or acceptable for legal cases.
* More reliable for detection of Methamphetamine and Opiates, less reliable for THC or Cannabinoids (2004)