Confirmation of High Specificity of an Automated Enzyme Immunoassay Test for Serological Diagnosis of Syphilis: Retrospective Evaluation Versus Results After Implementation

L. van Dommelen*, C.J.P.A. Hoebe, F.H. van Tiel, C. Thijs, V.J. Goossens, C.A. Bruggeman, I.H.M. van Loo

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background: The optimal algorithm for serological syphilis screening is still a matter of debate. We have previously evaluated the performance of the Bioelisa Syphilis 3.0, using a selection of archived sera, and in this study compare these results with the Bioelisa results after clinical implementation.

Methods: All Bioelisa Syphilis 3.0 results obtained since clinical implementation were analyzed. Bioelisa-positive or borderline samples were retested using Treponema pallidum particle agglutination, rapid plasma reagin test, fluorescent treponemal antibody-absorption test, and/or immunoblot. On sera sent in together with cerebrospinal fluid, occasionally both the T. pallidum particle agglutination and Bioelisa were performed.

Results: The Bioelisa was performed on 14,622 sera. Bioelisa-positive samples, which were not retested by the previously described assays, were withdrawn from the database (n = 36). In 1.3% of the samples (187/14,586), the Bioelisa was positive or borderline and, ultimately, 115 sera were considered true positive (prevalence 0.8%). The specificity of the Bioelisa was 99.5%.

Conclusions: Based on the results of all performed diagnostic assays, the specificity of the Bioelisa of 99.5% is very consistent with that found in the initial study (100%; 95% confidence interval was 98.0%-100%). Interpreting (positive) test results is difficult in the absence of a gold standard, especially when the disease prevalence is low. Results should be viewed in the light of the patients' characteristics.

Original languageEnglish
Pages (from-to)120-122
Number of pages3
JournalSexually Transmitted Diseases
Issue number3
Publication statusPublished - Mar 2015


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