Serologic diagnosis of syphilis: an update.

Tests used in the serologic diagnosis of syphilis can be divided into two main groups: nontreponemal (reagin) tests and treponemal tests. The most widely used nontreponemal test is the Venereal Disease Research Laboratory (VDRL) slide test, and the standard treponemal test is the manual fluorescent treponemal antibody-absorption (FTA-ABS) test. These tests and other newer tests available for the serologic diagnosis of syphilis are reviewed, with emphasis placed on their current clinical usefulness.