Phase 2: in field work
In total, 97 volunteers (54% women) underwent both sniffer dog and RAD test (results are reported in Tables Summary of results from volunteers who tested positive on the rapid antigen test (RAD) and were sniffed by the sniffer dogs in the field work, grouped based on being sniffed by a single dog (one) or multiple dogs (multiple).n. correct choices/total positive = 82% (13/16)n. incorrect choices/total positive = 18% (3/16)n. correct choices/total positive = 100% (1/1)n. incorrect choices/total positive = 0% (0/1)n. correct choices/total positive = 100% (10/10)n. incorrect choices/total positive = 0% (0/10)n. correct choices/total positive = 100% (1/1)n. incorrect choices/total positive = 0% (0/1)Names of sniffer dogs with wrong choices are displayed in bold.Summary of results from volunteers who tested negative on the rapid antigen test (RAD) and were sniffed by the sniffer dogs in the field work, grouped based on being sniffed by a single dog (one) or multiple dogs (multiple).n. correct choices/total negative = 100% (2/2)n. incorrect choices/total negative = 0% (0/2)n. correct choices/total negative = 95% (20/21)n. incorrect choices/total negative = 5% (1/21)n. correct choices/total negative = 100% (7/7)n. incorrect choices/total negative = 0% (0/7)n. correct choices/total negative = 100% (1/1)n. incorrect choices/total negative = 0% (0/1)Name of sniffer dogs with wrong choices are in bold.The rapid antigen test gave a positive result in 39 volunteers (40%) (Table Of the 58 (60%) volunteers tested negative on rapid antigen test (Table Regarding the overall Se and Sp of sniffer dogs working in field, the Se was 89% (95% CI 78–95%) and the Sp was 95% (95% CI 88–98%). Thus, the 95% CI did not overlap by 50%, being far from randomness.Overall, there was an almost perfect concordance between the dogs’ detection and RAD results (kappa 0.84, se 0.047, p = 0.001).