A 41-year-old woman is seen in a sexual health clinic with vaginal discharge and is diagnosed and treated for chlamydia. Laboratory studies sent at that time show a positive treponemal enzyme immunoassay (EIA), a positive Venereal Disease Research Laboratory (VDRL) test at a titer of 1:16, and a negative HIV-1/2 antigen-antibody test. She had a negative syphilis VDRL test 5 years ago but has not had any additional syphilis testing until now. She has never been treated for syphilis and has no past or current signs or symptoms consistent with syphilis. Her physical examination is normal, and a pregnancy test is negative. She does not have any antibiotic allergies.