Percentage of men who have sex with men with active syphilis

Measurement tools: Routine health information systems, sentinel surveillance or special surveys.
How to measure: The traditional approach to determining seroprevalence has been to screen with a non-treponemal test that measures reaginic antibody (e.g., VDRL or RPR) and confirm positive results with a treponemal test that measures treponemal antibody (e.g., TPHA, TPPA, EIA, or rapid treponemal test). Newer, rapid treponemal tests are comparatively easy to use, which encourages the use of these tests for screening, ideally paired with a non-treponemal test that detects reaginic antibody. Whichever approach is used, the proposed indicator requires both a positive non-treponemal test AND a positive treponemal test to give a proxy for active infection. If RPR testing is performed, itshould be titrated and be ≥1:8 to be certain of active syphilis.
Just a non-treponemal test, or just a treponemal test, while useful in some situations for therapeutic purposes, is not sufficiently specific for surveillance of men who have sex with men. The requirement for both a positive non-treponemal test and a positive treponemal test in men who have sex with men differs from the indicator on syphilis testing in antenatal care attendees because men who have sex with men are more likely to have a history of previous infection. A positive treponemal test measures lifetime exposure, whereas the non-treponemal test is a better indicator of active infection.

Data Quality Control and Notes for the Reporting Tool
It is important NOT to count multiple tests run on the same patient. That is, if a person has been tested more than once in the past 12 months, they should not be counted more than once.