Elecsys Syphilis Signal-to-Cutoff
Description
Supplementary file 1: Data for 19,368 syphilis screening tests on 15,764 unique patients using the Roche Diagnostics Elecsys Syphilis assay. All laboratory data involve analysis on plasma or serum. Specific data fields include: unique patient identification number (deidentified), whether result was first or only syphilis screening test performed for the specific patient within the retrospective timeframe or a repeat test (with days after initial test recorded), age in years, sex (as recorded in the electronic medical record), clinical location/unit at time of testing (emergency department, infectious disease clinic, obstetrics, inpatient, or outpatient clinic other than infectious diseases or obstetrics), syphilis screening result (negative or positive), and S/CO value for the syphilis screening. Supplementary file 2: Data for 355 positive syphilis screening tests on 270 unique patients using the Roche Diagnostics Elecsys Syphilis assay. All laboratory data involve analysis on plasma or serum. Specific data fields include: unique patient identification number (deidentified), whether result was first or only syphilis screening test performed for the specific patient within the retrospective timeframe or a repeat test, age in years, sex (as recorded in the electronic medical record), clinical location/unit at the time of syphilis testing (emergency department, infectious disease clinic, obstetrics, inpatient, or outpatient), S/CO value, results of subsequent testing in the reverse algorithm cascade (classified into the following categories: RPR reactive with specific titer noted, RPR and TP-PA non-reactive, RPR non-reactive / TP-PA inconclusive, and RPR non-reactive / TP-PA reactive), specific category (including RPR reactive results broken down into 1:1 to 1:8 and 1:16 or higher subgroups), and clinical notes.
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Steps to reproduce
During the retrospective analysis period (April 2, 2018 through May 14, 2021), syphilis screening using the reverse algorithm was performed using the Roche Diagnostics Elecsys Syphilis assay (Roche Diagnostics, Indianapolis, IN). A reporting tool within the electronic medical record, known as Epic Reporting Workbench, was used to identify all syphilis antibody screening tests performed in the retrospective timeframe. The Elecsys Syphilis assay is an immunoassay for the detection of the total antibodies (especially IgG and IgM) to Treponema pallidum in the human plasma and serum and outputs a single S/CO ratio that translates into a positive or negative qualitative result. An S/CO ratio of 1.00 or greater on the Elecsys assay is considered positive, with repeat testing to verify the result. For samples with a positive syphilis antibodies screen, subsequent confirmatory testing includes first an RPR (Bio-Rad Laboratories Bioplex 220 Syphilis Total & RPR Assay, Redmond, WA). If RPR is reactive, no further testing is done. If RPR is non-reactive, then TP-PA testing (referred to reference laboratory, ARUP Laboratories, Salt Lake City, UT) is then done. Data from Reporting Workbench were supplemented with chart review to determine clinical status and to verify if additional syphilis testing had been ordered at another institution.