Dark ground microscopy and treponemal serology for diagnosis of early syphilis

There has been a recent increase in the incidence of infectious syphilis in the UK, especially in homosexual men. Dark ground microscopy (DGM) provides immediate diagnosis but requires a dark field microscope and trained staff and, because syphilis has been uncommon in the UK until recently, many genitourinary medicine physicians are unskilled in its use. Other direct detection methods such as direct fluorescent antibody staining (DFA-Tp) or polymerase chain reaction (PCR) are more difficult or slow and serological tests have limited sensitivity for primary syphilis. Workers in London have confirmed the usefulness of DGM.

Their retrospective case note review included 50 patients with primary syphilis (PS) and 36 with secondary syphilis (SS). The diagnosis of...