Table 2.

Sensitivity of RT-PCR, RRT-PCR, and VI for two IBV viruses.

Virus dilution	M41				IS/885
	RT-PCR (S1)	RT-PCR (N)	RRT-PCR (N) Cta	VIb	RT-PCR (S1)	RT-PCR (N)	RRT-PCR (N) Ct	VI
10−1	+	+	21.3 ± 0.5	5/5	+	+	21.2 ± 0.3	1/5
10−2	+	+	23.7 ± 0.32	5/5	−	+	24.5 ± 0.15	0/4
10−3	+	+	27.6 ± 0.19	5/5	−	−	28.4 ± 05	3/5
10−4	−	+	31.3 ± 0.12	5/5	−	−	31.7 ± 0.3	1/5
10−5	−	+	33.3 ± 0.36	5/5	−	−	34 ± 0.1	0/5
10−6	−	+	34.7 ± 0.12	5/5	−	−	−	0/5
10−7	−	−	34.9 ± 0.23	5/5	−	−	−	0/5
10−8	−	−	−	0/5	−	−	−	0/5

^aCt: average cycle threshold ± standard deviation.

^bNo. of IBV − positive/total.