Table 3

Amount of DNA per PCR	PCR assay
	pXO1-MGB PCR		pXO2-MGB PCR		Ba chr-MGB PCR
	+ve’s^a	Mean C_T^b	+ve’s	Mean C_T	+ve’s	Mean C_T
100 fg	10/10	32.9^c (0.20)	10/10	34.02^c (0.39)	10/10	35.76^c (0.41)
10 fg	8/10	37.37 (2.7)	8/10	36.83 (2.79)	4/10	38.24 (1.92)

^aNo. of PCR positives from 10 replicates. ^bC_T value. PCR cycle number in which fluorescence first detected in 45 cycle PCR. Variance of mean in paranthesis ^cAt 100 fg of DNA, the pXO1 PCR was significantly lower than pXO2 PCR which in turn was significantly lower than Ba chr-MGB PCR (at 95% C.I.)

Table 3: Result from limit of detection experiments (purified B. anthracis Ames strain DNA) of each B. anthracis PCR.