Table 3.

Kappa test analysis between results obtained in different sets of diagnostic methods for the 147 cows belonging to infected herds.

a. Contingency table
IMS-IS1 PCR	Fecal culture			Milk culture			ELISA
	+	−		+	−		+	−
+	15	65	80	2	78	80	20	60	80
−	2	65	67	0	67	67	6	61	67
	17	130	147	2	145	147	26	121	147

b. Kappa coefficient and proportion of agreement
IMS-IS1 PCR	Fecal culture	Milk culture	ELISA
Kappa (95% CI)	0.15 (0.05–0.24)	0.02 (0.01–0.05)	0.15 (0.03–0.27)
Concordant results	80	69	81
Proportion of agreement	0.54	0.47	0.55