Table 2.

Sensitivity and specificity of rotavirus A detection in control viral antigen samples and in positive faecal sample by CB‐ELISA method and commercial DAS‐ELISA kit

Control Ag faeces dilution	CB‐ELISA absorbance, NA and %B*					DAS‐ELISA kit†
	Wells incubated with		NA	%B	E	cA	E
	SwSneg.	SwSpos.
DAS‐ELISA pos. Ag	0.772	0.022	0.750	97.1	+	1.928	+
DAS‐ELISA neg. Ag	0.012	0.011	0.001	−	−	0.002	−
Rota V‐Ag	1.595	0.075	1.520	95.3	+	2.905	+
TGE V‐Ag	0.005	0.005	0.000	−	−	0.001	−
PEDV‐Ag	0.006	0.024	−0.018	−	−	0.001	−
Faeces – 2×	2.154	0.155	1.999	92.8	+	3.285	+
4×	2.124	0.110	2.014	94.8	+	3.251	+
8×	1.897	0.072	1.825	96.2	+	2.987	+
16×	1.764	0.056	1.708	96.8	+	1.745	+
32×	1.455	0.015	1.440	99.0	+	0.817	+
64×	1.058	0.009	1.049	99.1	+	0.385	+
128×	0.689	0.007	0.682	99.0	+	0.186	−
256×	0.419	0.006	0.413	98.6	+	0.083	−
512×	0.216	0.004	0.212	98.1	+	0.044	−
1024×	0.111	0.010	0.101	91.0	+	0.023	−

*Samples of crude V‐Ag (rota A, TGEV, PEDV), and a faecal sample from experimentally infected piglet diluted twofold 2× to 1024× were examined by CB‐ELISA in a mixture with SwSneg./SwSpos. diluted 40×. Samples were evaluated as positive at NA values >0.1 and %B > 50.

†Samples examined by commercial DAS‐ELISA kit for rotavirus A detection. According to corrected absorbance (cA = A tested sample − A neg. Ag) samples were assessed as positive at cA > 0.3; dubious at cA = 0.2–0.3 and negative at cA < 0.2.

E, final evaluation of samples tested (positive +; negative −); DAS‐ELISA, double antibody sandwich ELISA, CB‐ELISA, competitive blocking ELISA; TGEV, transmissible gastroenteritis virus; PEDV, porcine epidemic diarrhoea virus; NA, net absorbance; differences of mean absorbances (A) in wells incubated in the presence of rotavirus A‐negative or ‐positive blood sera (NA = A SwSneg. − A SwSpos.); Samples with positive values are in bold.

%B, percentage of absorbance blocking in wells incubated with SwSpos. in comparison with the wells containing SwSneg.