Which diagnostic test is commonly used for screening of syphilis?

The VDRL (Veneral Disease Research Laboratory) test is a non-treponemal screening test that is commonly used for the diagnosis of syphilis. It detects nonspecific antibodies that are produced in response to the infection. The test is especially useful due to its ease of use and ability to be performed in a variety of healthcare settings, making it a practical choice for initial screening.

Positive results from the VDRL test often require confirmation with a more specific test, such as the FT-ABS (Fluorescent Treponemal Antibody Absorption) test or other treponemal tests, which confirm the presence of antibodies specific to the Treponema pallidum bacterium that causes syphilis. This two-step approach helps to prevent false-positive results, which can occur with the VDRL test due to cross-reactivity with other conditions.

Other testing methods, such as darkfield microscopy, PCR testing, or treponemal tests like FT-ABS, play roles in the diagnostic process but are not primarily used for routine screening in the same way the VDRL test is. Darkfield microscopy requires a direct examination of lesions and is not suitable for all patients. PCR testing, while highly sensitive