The Venereal Disease Research Laboratory (VDRL) test is a non-treponemal serological test commonly used for screening syphilis. It detects antibodies produced in response to cellular damage caused by Treponema pallidum, the causative organism of syphilis. The test is rapid, inexpensive, and sensitive, making it suitable for early detection and screening in asymptomatic individuals. However, it requires confirmation with treponemal tests due to possible false positives. The Widal test is for typhoid, Mantoux for tuberculosis, and ELISA for HIV, hence irrelevant for syphilis screening.

Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson et al., 20th Edition.