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Table 1 Positive predictive values (PPV), negative predictive values (NPV), sensitivity and specificity are reported for concordance of expected and detected opioids, fentanyl, and heroin in samples submitted to DCS in Toronto, ON October 2019 to April 2020 (N = 555)

From: Diverse psychotropic substances detected in drug and drug administration equipment samples submitted to drug checking services in Toronto, Ontario, Canada, October 2019–April 2020

Opioid

Detected

Not detected

Total

PPV

94.08% (90.92, 96.18)

Expected

270

17

287

NPV

91.79% (88.2, 94.36)

Not expected or unknown

22

246

268

Sensitivity

92.47% (88.82, 95.22)

Total

292

263

N = 555

Specificity

93.54% (89.85, 96.19)

Fentanyl

Detected

Not detected

Total

PPV

93.31% (89.91, 95/62)

Expected

251

18

256

NPV

93.01% (89.71, 95.31)

Not expected or unknown

20

266

299

Sensitivity

92.62% (88.83, 95.43)

Total

271

284

N = 555

Specificity

93.66% (90.17, 96.20)

Heroin

Detected

Not detected

Total

PPV

100%

Expected

8

0

8

NPV

79.52% (78.74, 80.29)

Not expected

112

435

547

Sensitivity

6.67% (2.92, 12.71)

Total

120

435

N = 555

Specificity

100% (99.16, 100)