Evaluation of a commercial ELISA kit for detection of antibodies against Toxoplasma gondii in serum, plasma and meat juice from experimentally and naturally infected sheep

Table 2 Comparison of PrioCHECK ® Toxoplasma Ab SR ELISA-results (cut-off PP 20) from 96 sheep from Switzerland (Group 2) to results obtained by IFAT, IHA (not performed with meat juice samples) and real-time PCR, and inter-rater agreement (kappa value)

		IFAT serum cut-off 1:40			IFAT serum cut-off 1:80			IHA serum cut-off 1:80			Real-time PCR brain/muscle
A		positive	negative	total	positive	negative	total	positive	negative	total	positive	negative	total
ELISA serum	positive	18	0	18	18	0	18	18	0	18	11	7	18
	negative	0	78	78	0	78	78	0	78	78	0	78	78
	total	18	78	96	18	78	96	18	78	96	11	85	96
	Kappa	1.0			1.0			1.0			0.719
	Standard Error	0			0			0			0.0983
	95% CI	1.0-1.0			1.0-1.0			1.0-1.0			0.526-0.911
			IFAT meat juice cut-off 1:40			IFAT meat juice cut-off 1:80			Real-time PCR brain/muscle
B			positive	negative	total	positive	negative	total	positive	negative	total
ELISA meat juice 1:10	positive		18	2	20	15	5	20	11	9	20
	negative		0	76	76	0	76	76	0	76	76
	total		18	78	96	15	81	96	11	85	96
	Kappa		0.934			0.826			0.659
	Standard Error		0.0458			0.0746			0.102
	95% CI		0.845-1			0.68-0.972		0.46-0.859
ELISA meat juice 1:20	positive		17	1	18	15	3	18	11	7	18
	negative		1	77	78	0	78	78	0	78	78
	total		18	78	96	15	81	96	11	85	96
	Kappa		0.932			0.890			0.719
	Standard Error		0.0478			0.0619			0.0983
	95% CI		0.838-1			0.769-1			0.526-0.911

A: serum samples; B: meat juice samples at a dilution of 1:10 and 1:20. CI: confidence interval.

ISSN: 1756-3305