Diagnostic value of Treponema pallidum PCR test in real practice.

The PCR test has a high diagnostic value when performed on ulcer exudates in patients with primary syphilis. Its most relevant advantages in clinical practice are the possibility of an early diagnosis before serological tests during the window period, the ability to confirm reinfections in patients with persistent positivity of reaginic antibodies and a history of treated syphilis. Nevertheless, given that a negative PCR test may not rule out infection by Treponema pallidum, serologic tests are still necessary for everyday practice.