Table 2 Association of drug check results and overdose as well as naloxone administration among clients of Insite who used a fentanyl drug checking service in Vancouver, Canada
Drug check result | Total | Overdose Yes; n (%)a | Overdose No; n (%) | Odds ratio (95% CI) | P valueb |
 Overall | |||||
  Positive | 1028 | 115 (11.19) | 913 (88.81) | 5.97 (2.41–14.78) | 0.0001 |
  Negative | 242 | 5 (2.07) | 237 (97.93) | Ref. |  |
 Pre-consumption | |||||
  Positive | 357 | 7 (1.96) | 350 (98.04) | 4.60 (0.26–81.21)c | 0.297 |
  Negative | 107 | 0 (0.00) | 107 (100.00) | Ref. |  |
 Post-consumption | |||||
  Positive | 649 | 108 (16.64) | 541 (83.36) | 4.95 (1.97–12.39) | 0.0001 |
  Negative | 129 | 5 (3.88) | 124 (96.12) | Ref. |  |
Drug check result | Total | Naloxone administered Yes; n (%) | Naloxone administered No; n (%) | Odds ratio (95% CI) | P valueb |
 Overall | |||||
  Positive | 1026 | 87 (8.48) | 939 (91.52) | 4.42 (1.77–11.02) | 0.001 |
  Negative | 244 | 5 (2.05) | 239 (97.95) | Ref. |  |
 Pre-consumption | |||||
  Positive | 355 | 3 (0.85) | 352 (99.15) | 1.83 (0.09–35.87)c | 0.688 |
  Negative | 109 | 0 (0.00) | 92 (100.00) | Ref. |  |
 Post-consumption | |||||
  Positive | 649 | 84 (12.94) | 565 (87.06) | 3.68 (1.46–9.27) | 0.003 |
  Negative | 129 | 5 (3.88) | 124 (96.12) | Ref. |  |