Table 2.

Analytical sensitivities of N-PCR and Q-PCR using DNA extracted from different dilutions of S. Typhi cultures and spiked blood samples

Dilution factor	Organisms/ml	Result determined by
		Bacterial culture		Spiked blood
		N-PCR	Q-PCR (Cta)	N-PCR	Q-PCR (Cta)
Stock	4.2 × 108	+	+ (16.0)	NA	NA
10−1	4.2 × 107	+	+ (19.1)	+	+ (19.5)
10−2	4.2 × 106	+	+ (22.5)	+	+ (23.1)
10−3	4.2 × 105	+	+ (25.7)	+	+ (26.2)
10−4	4.2 × 104	+	+ (28.2)	+	+ (29.8)
10−5	4.2 × 103	+	+ (31.1)	+	+ (33.1)
10−6	4.2 × 102	+	+ (33.6)	+	+ (36.5)
10−7	4.2 × 101	+	+ (36.9)	-	- (39.2)
10−8	4.2 × 100	-	- (40.0)	-	- (40.0)

NA, not applicable

^aThe Ct cutoff value for positive result is ≤37