Evaluation of The Diagnostic Algorithms for Serodiagnosis of Syphilis

Abstract

We analyzed the performance parameters of the traditional and the reverse algorithms to find out which one is more convenient for serodiagnosis of syphilis. In total, 4789 serum samples were obtained in a cross-sectional study. Venereal Disease Research Laboratory (VDRL), Treponema pallidum Haemagglutination Assay (TPHA) and Chemiluminescent Microparticle Immunoassay (CMIA) tests were performed for every serum sample. In case of discordance between results, the TPHA was applied as a second treponemal test. Overall, 207 patients were serodiagnosed with syphilis. Among 4789 subjects tested, 125 (2.6%) and 206 (4.3%) were positive using the traditional algorithm and the reverse algorithm, respectively. The missed diagnosis rate of the traditional algorithm was 42.5%. The reverse algorithm had higher sensitivity than the traditional algorithm. Sensitivity levels of the traditional and the reverse algorithms were 57.49% and 99.85% respectively. The false positivity of the reverse algorithms was 0.02%.