Which test is used for initial screening of syphilis?

The nontreponemal serology tests, such as the VDRL (Venereal Disease Research Laboratory) and RPR (Rapid Plasma Reagin) tests, are widely utilized for the initial screening of syphilis due to their accessibility, cost-effectiveness, and speed in obtaining results. These tests detect nonspecific antibodies that may be present in the serum of individuals with syphilis, particularly during the early stages of the infection.

The use of nontreponemal tests is recommended in screening programs because they can also indicate the presence of active disease, allowing for timely diagnosis and treatment. If the screening results are positive, further confirmatory testing with treponemal tests, such as the FTA-ABS (Fluorescent Treponemal Antibody Absorption) test, is necessary to confirm the diagnosis of syphilis.

Other methods mentioned, such as darkfield detection and fluorescent antibody tests, are useful in certain contexts but are not typically employed as routine initial screening tests for syphilis. Darkfield microscopy requires live samples and is generally used for diagnosis in specific situations, while fluorescent antibody tests are more specialized and not used for initial screening.