TABLE 1.

Sensitivity of real-time PCR^a

No. of DNA copies	invA CT valueb				Mean ± SD invA CT value
	Expt 1	Expt 2	Expt 3	Expt 4
105	22.48	23.29	23.14	23.16	23.02 ± 0.37
104	26.63	26.74	26.77	26.90	26.76 ± 0.11
103	29.74	29.79	29.56	29.50	29.65 ± 0.14
102	33.31	33.06	32.35	32.99	32.93 ± 0.41
10	36.29	35.45	36.11	36.46	35.83 ± 0.44
2	37.73	36.53	36.27	36.33	36.72 ± 0.69
1	38.26	Neg	Neg	38.70	38.48 ± 0.31

^aThe lower limit of detection by the PCR method was determined by testing various concentrations of Salmonella Enteritidis DNA, ranging from 1 to 10⁵ copies per reaction. The assay was performed in quadruplicate.

^bThe C_T values were obtained from the 4 assays and represent the number of PCR cycles at which the fluorescence generated crossed the minimum threshold set for the assay. Neg, negative (no C_T value was displayed).