title: Evaluation of the passive particle agglutination test in the serodiagnosis and follow-up of syphilis.
abstract: We performed the present study to determine the rate of concordance of the fluorescent treponemal antibody absorption test (FTA-ABS) and of the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP) with the passive particle agglutination test (TP.PA) in patients with early syphilis and to observe the reactivity of the rapid plasma reagin (RPR), MHA-TP, and the TP.PA tests for 1 year after therapy. The study included 449 people who were given therapy if they had syphilis and followed up for 1 year. The rate of concordance of the TP.PA with the MHA-TP was 98.4%, and it was 98.9% with the FTA-ABS. During follow-up, a significant decrease of antibodies was found in 56%, 26%, and 70% of the patients when using the RPR, the MHA-TP, and the TP.PA, respectively. The TP.PA seems to be an adequate routine assay for the diagnosis of syphilis, being as sensitive as the FTA-ABS test in primary syphilis and as useful as the RPR test in monitoring therapy.
authors.affiliation: Sexually Transmitted Diseases Unit, Center of Malaria and Other Tropical Diseases, Institute of Hygiene and Tropical Medicine, Rua da Junqueira, No. 96, 1349-008, Lisboa, Portugal.
authors.forename: R R
authors.initials: RR
authors.lastname: Castro
authors.forename: E S
authors.initials: ES
authors.lastname: Prieto
authors.forename: I
authors.initials: I
authors.lastname: Santo
authors.forename: J
authors.initials: J
authors.lastname: Azevedo
authors.forename: F L
authors.initials: FL
authors.lastname: Exposto
mesh_terms: D000372:Agglutination Tests; D000907:Antibodies, Bacterial / Q000097:blood; D016508:Fluorescent Treponemal Antibody-Absorption Test; D006386:Hemagglutination Tests; D006801:Humans; D012698:Serologic Tests; D013587:Syphilis / Q000175:diagnosis*; D014210:Treponema pallidum / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial