Pathology and Clinical Governance, Australian Red Cross Lifeblood, West Melbourne, Victoria, Australia.
Clinical Microbiology, ACT Pathology, Garran, Australian Capital Territory, Australia.
J Clin Microbiol. 2024 Aug 14;62(8):e0047624. doi: 10.1128/jcm.00476-24. Epub 2024 Jul 15.
Using sequential immunoassays for the screening of blood donors is well described for viral serology testing but not for the screening of syphilis. In this study, we report the evaluation results and 2-year sequential testing data using two highly sensitive automated serology assays, the Alinity s Syphilis chemiluminescent immunoassay for screening, with all repeatedly reactive samples then tested on the Elecsys Syphilis electrochemiluminescence immunoassay. We screened 1,767,782 blood donor samples between 7 July 2021 and 6 July 2023 and found the Alinity false-positive rate to be low at 0.08% (1,456/1,767,782). The common false-positive rate between the two assays was also low (3.83%, 58/1,514). Concordantly reactive samples were further tested using a particle agglutination test, a rapid plasma reagin test, and a fluorescent treponemal antibody absorption test. There were 262/1,376 concordantly reactive Alinity and Elecsys blood donor samples with reactivity on one or more of the confirmatory tests. A total of 26/1,376 donors had a current syphilis infection, 152/1,376 reported a past history of syphilis and had been treated, and 84/1,376 did not report a past history of syphilis. We suggest that future studies could explore the use of sequential immunoassays to aid in the serodiagnosis for syphilis.
The serodiagnosis for syphilis usually follows two methodologies-a "traditional" algorithm using a non-treponemal test followed by confirmation using a treponemal test, or a "reverse" algorithm using a treponemal test followed by a non-treponemal test. There are limited reports in the literature of using a modified reverse algorithm (treponemal test followed by a second treponemal test), and to the best of knowledge, there are currently no published articles using two highly sensitive automated immunoassays to aid the serodiagnosis of syphilis. In addition, the particle agglutination (TPPA) assay is commonly used as a confirmatory test for the diagnosis of syphilis. With the withdrawal of the TPPA assay from Australia and presumably from the global market also, alternative testing algorithms are now required. This study provides proof of concept for using sequential immunoassays in the diagnosis of syphilis.
梅毒的血清学诊断通常遵循两种方法——一种是“传统”的方法，即先用非梅毒螺旋体试验，再用梅毒螺旋体试验确认；另一种是“反向”的方法，即先用梅毒螺旋体试验，再用非梅毒螺旋体试验。文献中关于使用改良反向算法（梅毒螺旋体试验后再进行第二次梅毒螺旋体试验）的报道有限，据了解，目前还没有使用两种高灵敏度自动化免疫分析来辅助梅毒血清学诊断的已发表文章。此外，粒子凝集（TPPA）试验通常被用作梅毒诊断的确认试验。随着 TPPA 检测试剂盒在澳大利亚和可能在全球范围内的撤出，现在需要替代的检测算法。本研究为梅毒的诊断提供了使用序贯免疫分析的概念验证。
