HOW SHOULD SYPHILIS SEROLOGY BE INTERPRETED?
Syphilis serological tests include a nontreponemal test, such as a rapid plasma reagin (RPR) test or a venereal disease research laboratory (VDRL) test, currently used in Canada only for testing of cerebrospinal fluid (CSF), and a treponemal test that detects treponemal-specific antibodies including fluorescent treponemal antibody absorption (FTA-ABS), Treponema pallidum particle agglutination, microhemagglutination for T pallidum, enzyme immunoassay (EIA) and line-blot immunoassay, such as INNO-LIA (Innogenetics, Belgium), with interpretation as shown in Tables 1 and 2. Two screening approaches for syphilis are used in Canada. Most jurisdictions use RPR as an initial screen, and confirm a reactive result with a treponemal test. Some jurisdictions have introduced EIA as the initial screen, with confirmation by another treponemal test because EIA has a higher sensitivity and specificity than RPR. Obtaining RPR titres is still necessary if the EIA is positive because they are used fo
