TABLE 3.

Summary of dog training on 24 Getxent tubes used in gas chromatography-mass spectrometry (GC-MS) analysis

	Dog 1	Dog 2	Dog 3	Total (%)	Mean (Q3–Q1)
Total runs on specified positive gargle samples (n=14)	99	94	71	264 (100)	20 (23)
Total runs with false positives	4	1	1	6 (2.3)	NA
Total runs on specified negative gargle samples (n=10)	55	60	47	162 (100)	16 (16)
Total runs with false negatives	6	2	4	12 (7.4)	NA

Using the discrepancy matrix, samples with a failure rate of dog alert above 15% were considered negative for the purpose of this analysis. Altogether, the model correctly classified 68% of the samples with F1 and Matthew's correlation coefficient scores of 0.69 and 0.37, respectively, considered to be a good concordance between the two methods (table 4). Individually, the Kappa agreement between the dogs and GC-MS was moderate: 0.503 for dog A, 0.510 for dog B and 0.412 for dog C.