Recently, saliva has been used to realise on-site tests with special devices that permit to perform drug assays immediately at the site of specimen collection. These assays on saliva proved to be sufficiently sensitive for the detection of recent cocaine and amphetamine abuse in suspected users. However, the application of on-site testing of saliva after controlled administration of amphetamine or related compounds was never performed.
Eight healthy volunteers, recreational users of 3,4-methylenedioxymethamphetamine (MDMA), were administered with an oral 100 mg dose in a double blind, cross-over with random treatment assignment, balanced with placebo clinical trial. Drugwipe® Amphetamines analytical device was wiped on the tongue of the subjects at different time-intervals ranging from 0 to 24 hours after administration. Furthermore, at each time, a saliva sample (1-2 ml) was obtained by spitting into a plastic tube. The test was reapplied in the laboratory by pipetting 2 ml of saliva on the device pad. The colour reaction in the test-area of the Drugwipe® was measured with the Drugread® hand photometer. Quantitative analyses of salivary samples were also performed by GC/MS. Drugwipe® performed better if applied to a saliva sample in the laboratory than directly on the tongue. At 1.5 and 4 hours after drug administration, 100% subjects gave a positive result, while at 6 hours after treatment 1 out of 8 subjects gave a negative result. At 24 hours, no positive results were observed. Saliva samples from placebo treatment never showed a false positive result. Negative results were observed when MDMA salivary concentrations were under 650 ng/ml.
Although the number of subjects participating in this study is limited, the results support saliva testing with Drugwipe® and Drugread® for monitoring MDMA in the early hours after its use. It may help to screen potentially intoxicated drivers in roadside on site- testing and in the workplace drug testing, when appropriate confirmation with a chromatographic method in saliva can be performed.
Taken from; http://www.tiaft.org/about/yscw2001_abstract08.php
I don't know how different the testing equipment is the police are using but I would want to be driving even 10 hours after dropping, let alone 5...