Analytical evaluation of a rapid on-site oral fluid drug test

There is a need for a reliable rapid on-site oral fluid test that can be used in police controls to detect impaired drivers. We evaluated the Varian Oralab6 and collected two oral fluid samples from 250 subjects, one with the Varian Oralab6 and one with the StatSure Saliva Sampler. The Oralab6 can detect six drug types: amphetamines, methamphetamine, cocaine, opiates, delta9-tetrahydrocannabinol (THC), and phencyclidine (PCP). On-site results were obtained within 10 to 15 min. The sample collected with StatSure was analyzed using liquid chromatography-tandem mass spectrometry after liquid-liquid extraction and these results were used as a reference to determine prevalence, sensitivity, and specificity. Two cut-off values were used in the evaluation. The Varian cut-off values were: amphetamine 50 ng/mL, cocaine 20 ng/mL, opiates 40 ng/mL, and THC 50 ng/mL. The DRUID cut-offs were: amphetamine 25 ng/mL, cocaine 20 ng/mL, opiates 20 ng/mL, and THC 1 ng/mL. Applying the first cut-offs, prevalence, sensitivity, and specificity were: amphetamine 10%, 76%, 100%; cocaine 23%, 34%, 100%; opiates 38%, 83%, 94%; and THC 18%, 41%, 99%. The DRUID cut-off values gave the following results: amphetamine 14%, 56%, 100%; cocaine 28%, 34%, 100%; opiates 49%, 68%, 98%, and THC 45%, 16%, 99%. The specificity of the Oralab6 is generally good. For both cut-offs, sensitivity was low for cocaine and THC. Therefore, the Varian Oralab6 test is not sensitive enough to be applied during roadside police controls.