Table 3

The diagnostic performance of the scent dogs in the triple-blind validation test

DogDogs’ indicationSniffed
RT-PCR positive
samples
Sniffed RT-PCR negative samplesSniffed samples/all presented samplesSniffed samples (% from all samples)Sesniff*
(95 % CI)
Spsniff
(95 % CI)
PPVsniff
(95% CI)
NPVsniff§
(95 % CI)
Seall
(95% CI)
Spall 10
(95% CI)
SiljaPositive
Negative
99811
206
107/114
217/306
324 (77)93%
(85% to 96%)
95%
(91% to 97%)
90%
(82% to 95%)
96%
(92% to 98%)
87%
(79% to 92%)
96%
(93% to 98%)
RelePositive
Negative
104718
197
111/114
215/306
326 (78)94%
(87% to 97%)
92%
(87% to 95%)
85%
(77% to 91%)
97%
(93% to 98%)
91%
(84% to 95%)
94%
(91% to 96%)
KostiPositive
Negative
99823
203
107/114
226/306
333 (79)93%
(85% to 96%)
90%
(85% to 93%)
81%
(73% to 87%)
96%
(92% to 98%)
87%
(79% to 92%)
92%
(89% to 95%)
E.T.Positive
Negative
90
12
23
201
102/114
224/306
326 (78)88%
(80% to 94%)
90%
(85% to 93%)
80%
(71% to 86%)
94%
(90% to 97%)
79%
(70% to 86%)
92%
(89% to 95%)
All dogsPositive
Negative
392
35
75
807
427/456
882/1224
1309 (78)92%
(89% to 94%)
91%
(89% to 93%)
84%
(81% to 87%)
96%
(94% to 97%)
86%
(82% to 89%)
94%
(92% to 95%)
  • *Sesniff, sensitivity on sniffed samples only.

  • †Spsniff, specificity on sniffed samples only.

  • ‡PPVsniff, positive predictive value on sniffed samples. Based on the prevalance rate of COVID-19 positive samples in our data (27%).

  • §NPVsniff, negative predictive value on sniffed samples: Based on the prevalence rate of COVID-19 positive samples in our data (27%).

  • ¶Seall, sensitivity on all randomised samples: 10. Spall, specificity on all randomised samples.

  • RT-PCR, reverse transcriptase-polymerase chain reaction.