Abstract

Performance Evaluation of the Elecsys Syphilis Assay for the Detection of Total Antibodies to Treponema pallidum Martin Enders a , Andrea Hunjet a , Michael Gleich b , Roland Imdahl b , Annelies Mühlbacher c , Harald Schennach c , Kriangsak Chaiwong d , Tasanee Sakuldamrongpanich d , Ajda Turhan e , Rüchan Sertöz e , Eva Wolf f , Wolfgang Mayer g , Chuanmin Tao h , Lan Lan Wang h , Simona Semprini i and Vittorio Sambri i a Laboratory of G. Enders & Colleagues, MVZ and Institute of Virology, Infectious Diseases and Epidemiology e.V., Stuttgart, Germany b Labor Schottdorf MVZ GmbH, Augsburg, Germany c Central Institute for Blood Transfusion and Immunology, Innsbruck, Austria d National Blood Center, Thai Red Cross Society, Bangkok, Thailand e Faculty of Medicine, Ege University, Izmir, Turkey f MUC Research GmbH, Munich, Germany g Immumed GmbH, Munich, Germany h West China Hospital, Sichuan University, Chengdu, China i The Greater Romagna Area Hub Laboratory, Unit of Microbiology, Pievesestina, Cesena, Italy T. S. Alexander , Editor ABSTRACT Syphilis is a health problem of increasing incidence in recent years that may have severe complications if not diagnosed and treated at an early stage. There are many diagnostic tests available for syphilis, but there is no gold standard, and diagnosis therefore usually relies upon a combination of tests. In this multicenter study, we evaluated the treponemal Elecsys syphilis assay for use in the diagnosis of syphilis in routine samples, i.e., when syphilis is suspected or during antenatal or blood donation screening. The sensitivity and specificity of the Elecsys syphilis assay were compared head to head with those of other treponemal assays used in routine clinical practice and were assessed in potentially cross-reactive samples from patients with Epstein-Barr virus, HIV, and Lyme disease. In a total of 8,063 syphilis-negative samples collected from routine diagnostic requests and blood donations, the Elecsys syphilis assay had a specificity of 99.88%. In 928 samples previously identified as syphilis positive, the sensitivity was 99.57 to 100% (the result is presented as a range depending on whether four initially indeterminate samples are included in the assessment). The specificity of the Elecsys syphilis assay in patients with other infections was 100%; no false-positive samples were identified.