[Implementation of the reverse screening syphilis algorithm in a clinical laboratory]

Rev Chilena Infectol. 2019 Aug;36(4):525-530. doi: 10.4067/S0716-10182019000400525.
[Article in Spanish]


Background: Syphilis remains a public health concern worldwide, the accuracy of diagnostic tests is critical for its successful control. Currently, there are two approaches to the diagnosis of syphilis using serological tests: the traditional algorithm and the reverse algorithm.

Aim: The goal of this study was to analyse the advantages and disadvantages in the implementation of the syphilis reverse-screening algorithm in an outpatient clinical laboratory.

Methods: An observational cross-sectional study was carried out analyzing 246 reactive sera from a total of 14700 requests for syphilis serology. Chemiluminescent assay ARCHITECT Syphilis TP, V.D.R.L. and FTA-Abs were performed.

Results: Among 246 reactive sera by ARCHITECT Syphilis TP, 129 were reactive and 117 were non-reactive by V.D.R.L. the last mentioned resulted in 97 reactive and 20 non-reactive by FTA-Abs, suggesting false positives (0.13%). Two patients with primary infection were detected, that were not detected by V.D.R.L. and one pregnant woman with primary infection with a high value S/CO and V.D.R.L.:1 dils.

Conclusions: Among the advantages of using a reverse algorithm were greater sensitivity in the detection of patients with primary syphilis; automation, complete traceability of the samples; objective interpretation and conclusive results.

Publication types

  • Observational Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Algorithms
  • Cross-Sectional Studies
  • Female
  • Humans
  • Luminescent Measurements
  • Male
  • Mass Screening / methods*
  • Middle Aged
  • Pregnancy
  • Sensitivity and Specificity
  • Syphilis / diagnosis*
  • Syphilis Serodiagnosis / methods*
  • Treponema pallidum / immunology
  • Treponema pallidum / isolation & purification*
  • Young Adult

Supplementary concepts

  • Syphilis, primary