Evaluation of a New Competitive Immunoassay (BioElisa Syphilis) for Screening for Treponema pallidum Antibodies at Various Stages of Syphilis

Abstract

The BioElisa Syphilis, a new competitive enzyme immunoassay (EIA) for Treponema pallidum whole antigen that uses specific human immunoglobulin G (IgG) antibodies as the competitor, was evaluated for potential use in screening for syphilis at various stages. The results obtained by this competitive EIA were compared with those obtained by the fluorescent treponemal antibody absorption (FTA-abs) test and the T. pallidum hemagglutination assay (TPHA). Serum samples from 434 patients with positive TPHA and FTA-abs test results, including patients with primary, latent, secondary, and tertiary syphilis and neurosyphilis, were investigated. Two samples tested negative by competitive EIA but were weakly reactive by the TPHA and the FTA-abs test. Sixteen serum samples from patients with clinically documented active syphilis, including several patients infected with human immunodeficiency virus, tested positive by the competitive EIA. There was a direct inverse correlation between EIA indices and titers in the TPHA and the FTA-abs test for all samples that tested positive. Specificity was assessed by testing 358 serum samples which tested negative for syphilis by TPHA andthe FTA-abs test, including 100 serum samples from patients with documented infectious or autoimmune diseases. Only two serum samples gave a weakly positive EIA result. Thus, competitive EIA had a sensitivity of 99.5% and a specificity of 99.4% relative to the results of the FTA-abs test and TPHA. Our evaluation shows that BioElisa Syphilis is a sensitive, specific, and simple assay for screening for syphilis.

Clinical utility of a competitive ELISA to detect antibodies againstTreponema pallidum

“…In previous studies (1,5,7,9), some ELISA tests were assessed but without establishing infection diagnosis guide- lines for their use as a screening test. Following the completion of the present evaluation, we proposed a protocol to be followed for the Enzygnost test ( Fig.…”

“…The RPR, MHA, and the FTA-ABS were performed according to the manufacturers' instructions (5). The ELISA was performed first with MegaFlex automated pipetting and then with the Behring ELISA Processor system (BEP III) (DadeBehring).…”

“…ELISA tests that can be readily automated (BioELISA Syphilis, Captia Syphilis, Enzygnost Syphilis, and ICE Syphilis) have recently become available (5)(6)(7)(8)(9). They could reduce the laboratory work but their utility to detect the infection in its different stages must be demonstrated.…”

Comparative Evaluation of Nine Different Enzyme-Linked Immunosorbent Assays for Determination of Antibodies against Treponema pallidum in Patients with Primary Syphilis

“…Tests based on antigens produced with recombinant DNA techniques from single genes like TmpA (7); the 4D antigen, a ring-forming decamer on the outer membrane (15); or a combination of different recombinant proteins have become available (23,24). Most of the new tests have been evaluated in comparison with a standard test (3,11,13,22,24), e.g., the MHA-TP, the VDRL, or the Capital G test, an ELISA-based test commercially available for more than 10 years. However, no comparative evaluation of these tests has been published yet.…”

Avaliação do uso de teste treponêmico imunoenzimático competitivo na triagem sorológica da sífilis em 23.531 soros de uma população de baixa prevalência

“…EBEL (1998) relatam perda de sensibilidade do mesmo teste no período de latência, bem como no soro de indivíduos submetidos a tratamento. Este autor relata ainda que os testes imunoenzimáticos têm sensibilidade similar ao FTA-ABS e ao TPHA, em todos os estágios da sífilis, com exceção da sífilis primária, período em que o teste tem baixa sensibilidade.…”