title: Analysis of 3 algorithms for syphilis serodiagnosis and implications for clinical management.
abstract: BACKGROUND
  Algorithms for the diagnosis of syphilis continue to be a source of great controversy, and numerous test interpretations have perplexed many clinicians.
  
  
  METHODS
  We conducted a cross-sectional study of 24 124 subjects to analyze 3 syphilis testing algorithms: traditional algorithm, reverse algorithm, and the European Centre for Disease Prevention and Control (ECDC) algorithm. Every serum sample was simultaneously evaluated using the rapid plasma reagin, Treponema pallidum particle agglutination, and chemiluminescence immunoassay tests. With the results of clinical diagnoses of syphilis as a gold standard, we evaluated the diagnostic accuracy of the 3 syphilis testing algorithms. The κ coefficient was used to compare the concordance between the reverse algorithm and the ECDC algorithm.
  
  
  RESULTS
  Overall, 2749 patients in our cohort were diagnosed with syphilis. The traditional algorithm had the highest negative likelihood ratio (0.24), a missed diagnosis rate of 24.2%, and only 75.81% sensitivity. However, both the reverse and ECDC algorithms had higher diagnostic efficacy than the traditional algorithm. Their sensitivity, specificity, and accuracy were 99.38%-99.85%, 99.98%-100.00%, and 99.93%-99.96%, respectively. Moreover, the overall percentage of agreement and κ value between the reverse and the ECDC algorithms were 99.9% and 0.996, respectively.
  
  
  CONCLUSIONS
  Our research supported use of the ECDC algorithm, in which syphilis screening begins with a treponemal immunoassay that is followed by a second, different treponemal assay as a confirmatory test in high-prevalence populations. In addition, our results indicated that nontreponemal assay is unnecessary for syphilis diagnosis but can be recommended for determining serological activity and the effect of syphilis treatment.
authors.affiliation: Zhongshan Hospital, Medical College of Xiamen University.
authors.forename: Man-Li
authors.initials: ML
authors.lastname: Tong
authors.forename: Li-Rong
authors.initials: LR
authors.lastname: Lin
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Liu
authors.forename: Hui-Lin
authors.initials: HL
authors.lastname: Zhang
authors.forename: Song-Jie
authors.initials: SJ
authors.lastname: Huang
authors.forename: Yu-Yan
authors.initials: YY
authors.lastname: Chen
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Guo
authors.forename: Ya
authors.initials: Y
authors.lastname: Xi
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.forename: Fu-Yi
authors.initials: FY
authors.lastname: Chen
authors.forename: Ya-Feng
authors.initials: YF
authors.lastname: Zhang
authors.forename: Qiao
authors.initials: Q
authors.lastname: Zhang
authors.forename: Tian-Ci
authors.initials: TC
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D044967:Serum / Q000276:immunology; D013588:Syphilis Serodiagnosis / Q000379:methods*; D014210:Treponema pallidum / Q000276:immunology*; D055815:Young Adult
keywords: nontreponemal antibody test; serodiagnosis; syphilis; treponemal antibody test