A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid

Abstract

RationaleStandardized Field Sobriety Tests (SFST) and oral fluid devices are used to screen for driving impairment and roadside drug detection, respectively. SFST have been validated for alcohol, but their sensitivity to impairment induced by other drugs is relatively unknown. The sensitivity and specificity for Δ9-tetrahydrocannabinol (THC) of most oral fluid devices have been low.ObjectiveThis study assessed the effects of smoking cannabis with and without alcohol on SFST performance. Presence of THC in oral fluid was examined with two devices (Dräger Drug Test® 5000 and Securetec Drugwipe® 5).MethodsTwenty heavy cannabis users (15 males and 5 females; mean age, 24.3 years) participated in a double-blind, placebo-controlled study assessing percentage of impaired individuals on the SFST and the sensitivity of two oral fluid devices. Participants received alcohol doses or alcohol placebo in combination with 400 μg/kg body weight THC. We aimed to reach peak blood alcohol concentration values of 0.5 and 0.7 mg/mL.ResultsCannabis was significantly related to performance on the one-leg stand (p = 0.037). Alcohol in combination with cannabis was significantly related to impairment on horizontal gaze nystagmus (p = 0.029). The Dräger Drug Test® 5000 demonstrated a high sensitivity for THC, whereas the sensitivity of the Securetec Drugwipe® 5 was low.ConclusionsSFST were mildly sensitive to impairment from cannabis in heavy users. Lack of sensitivity might be attributed to tolerance and time of testing. SFST were sensitive to both doses of alcohol. The Dräger Drug Test® 5000 appears to be a promising tool for detecting THC in oral fluid as far as correct THC detection is concerned.

Cannabinoids in oral fluid by on-site immunoassay and by GC-MS using two different oral fluid collection devices

“…Similarly, diagnostic sensitivity, specificity, and efficiency improved in occasional and frequent smokers when considering samples collected up to 6 or 8h post dose, due to the higher incidence of true positive tests. This is consistent with two prior studies that documented higher sensitivities in samples collected recently after smoking [18,12]. …”

“…and A-Concateno DDS devices achieved ≥80% efficiency, sensitivity was only 69.2% and 37.8%, respectively. Overall, the authors concluded that the DrugTest 5000 achieved the best diagnostic efficiency for OF cannabinoids detection [13,17,16,18]. …”

“…Others also evaluated this newest DrugTest 5000 version (5 μg/L THC screening cutoff) and reported diagnostic sensitivity, specificity, and efficiency of 53-93, 71-99 and 84-94.3%, respectively, with OF THC confirmation cutoffs of 1-10 μg/L [12-13,16-17]. Recency of smoking was shown to impact diagnostic sensitivity and efficiency [12,18]. …”

Conducting Rapid Street Assessment of Drug Users in New York City Using Oral Fluid and Brief Interviews: A Feasibility Study

“…Previous studies have reported the low sensitivity of saliva screening tests for benzodiazepines 44,46 and for marijuana 43,46,47 in field settings. This was reflected in the findings of the current study.…”

The relationship between observed signs of impairment and THC concentration in oral fluid

“…In order to increase the sensitivity of SFSTs for THC, the addition of some tests and observations has been suggested, such as "head movements or jerks" (Papafotiou et al, 2005a(Papafotiou et al, , 2005b or a series of observations conducted by the physician as part of the Norwegian clinical test of impairment . Even with these extra observations, however, THC impairment is difficult to detect, particularly at lower THC concentrations (Bosker et al, 2012).…”