Table 2. PCR detection rates in seropositive samples taken from patients in different stages of syphilis.

Syphilis stage (total no. of seropositive samples)	Swab PCR positivity rate (total no. of positive samples/ total no. of samples)	Whole blood PCR positivity rate (total no. of positive samples/ total no. of samples)
Primary stage (n = 292)	84.3% (166/197)	42.1% (40/95)
Secondary stage (n = 148)	75.9% (41/54)	41.5% (39/94)
Undetermined stage (n = 211)	64.1% (50/78)	21.1% (28/133)
Total (n = 651)	78.1% (257/329)	33.2% (107/322)