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Table 2 Estimated Odds Ratios (OR) and 95% Confidence Intervals (CI) in Adjusted and Unadjusted Logistic Regression Models for THC Positivity in Blood given Oral Fluid Concentration (ng/ml), Continental United States, Nighttime Weekend and Daytime Friday, 2013–2014

From: Validity of oral fluid test for Delta-9-tetrahydrocannabinol in drivers using the 2013 National Roadside Survey Data

  Model 1 (n = 4596) Model 2 (n = 4433) Model 3 (n = 4415)
OR (95% CI) OR (95% CI) OR (95% CI)
Positive oral fluid test result 28.46 (13.86, 58.46) 12.10 (5.15, 28.41) 11.36 (7.32, 17.65)
Log(oral fluid THC) (log-ng/ml) 1.82 (1.48, 2.24) 1.93 (1.51, 2.47) 1.91 (1.68, 2.17)
Blood alcohol concentration (ng/dl)
 0   Ref Ref
 1–39   0.88 (0.20,3.82) 0.85 (0.39, 1.82)
 40+   0.19 (0.05, 0.72) 0.19 (0.10, 0.38)
Last time used marijuana
 Over a year/Never   Ref Ref
 Over a Month   3.87 (2.26, 6.61) 3.91 (2.95, 5.16)
 Past 2 days to a month   8.78 (5.40, 14.26) 8.78 (6.81, 11.33)
 Past 24 Hours   25.16 (14.26, 44.41) 26.44 (19.64, 34.59)
Age (years)
 16–20    Ref
 21–34    1.27 (0.96, 1.68)
 35–54    1.16 (0.84, 1.59)
  ≥ 55    0.96 (0.63, 1.45)
Gender (Male vs. Female)    0.99 (0.81, 1.20)
Race
 Black    Ref
 White    0.57 (0.46, 0.71)
 Other Race    0.69 (0.52, 0.91)
AUC (95% CI) 0.87 (0.82, 0.91) 0.94 (0.91, 0.97) 0.95 (0.92, 0.98)