one step anti-syphilis test is a rapid direct binding test for the visual detection of anti-syphilis in serum as an aid in the diagnosis of syphilis infection. test results are read visually without any instrument. it is based on the principle of double antigen sandwich immunoassay for determination of syphilis antibodies in serum. purified recombinant syphilis antigens are employed to identify anti-syphilis antibodies specifically.