 Blood tests are divided into nontreponemal and treponemal tests . Nontreponemal tests are used initially , and include venereal disease research laboratory ( VDRL ) and rapid plasma reagin tests . As these tests are occasionally false positives , confirmation is required with a treponemal test , such as treponemal pallidum particle agglutination ( TPHA ) or fluorescent treponemal antibody absorption test ( FTA @-@ Abs ) . False positives on the nontreponemal tests can occur with some viral infections such as varicella ( chickenpox ) and measles , as well as with lymphoma , tuberculosis , malaria , endocarditis , connective tissue disease , and pregnancy . Treponemal antibody tests usually become positive two to five weeks after the initial infection . Neurosyphilis is diagnosed by finding high numbers of leukocytes ( predominately lymphocytes ) and high protein levels in the cerebrospinal fluid in the setting of a known syphilis infection . 
