1313. Screening Veterans for Syphilis: Implementation of the Reverse Sequence Algorithm
Session: Poster Abstract Session: Clinical Infectious Diseases: Sexually Transmitted Infections
Friday, October 28, 2016
Room: Poster Hall
Posters
  • idweek.poster.10-21-16.pdf (671.7 kB)
  • Background: The incidence of syphilis in the United States is increasing, making accurate diagnosis essential. Some laboratories are utilizing the reverse syphilis screening (RSS) algorithm, which may lead to diagnostic dilemmas when there are discordant results between the treponemal and nontreponemal serologic tests. The objective of this study was to assess the impact of RSS implementation in a Veterans Affairs (VA) population and to characterize veterans with discordant results.

    Methods: We performed a retrospective review of all veterans tested for syphilis at the Durham VA Medical Center (DVAMC) between September 1, 2009 and August 31, 2015. Discordant results were defined as a reactive Treponema pallidum IgG enzyme immunoassay (BioPlex¨ 2200 Syphilis IgG Kit, Bio-Rad), followed by a non-reactive VDRL. TPPA testing was performed to determine true positives. Data were extracted using a systematic query of the electronic medical record, supplemented by manual record review for a random sample of veterans with discordant serologic testing.

    Results: During the study period, 627/11,162 (5.6%) syphilis IgG tests were reactive. Of these, 179 (28.5%) had reactive VDRLs versus 448 (71.5%) with non-reactive VDRLs. Among the 448 veterans with discordant tests, 378 (84.3%) had reactive TPPA results (Fig 1). From a random sample of 80 veterans with discordant results: average age was 61.8 years, 95% were men, and 20% were HIV-infected. TPPA was reactive in 86.3%. Reason for testing was to evaluate psychiatric/neurologic symptoms in 33%, routine screening/new sexual partner in 29%, genital symptoms in 5%, workup for another condition in 5%, and 29% had no clear reason for testing documented. Lumbar puncture was performed or attempted in 12.5% of cases. Previous treatment was noted in 45% of discordant cases, while 39% did not know or were not asked. Overall, treatment was initiated for 25% of veterans with discordant results (Fig 2).

    Conclusion: We found a high rate of reactive syphilis IgG tests among veterans using the RSS. Among those with discordant results, the majority represented true positives although many of these veterans had been previously treated. Implementation of the RSS led to syphilis treatment for one in four veterans with discordant results.

    Figure 1. Reactive Syphilis Results

    Description: Macintosh HD:Users:meredithclement:Documents:Syphilis Project VA:figure1.jpg

    Figure 2. Discordant Syphilis Serologic Testing

    Description: Macintosh HD:Users:meredithclement:Documents:Syphilis Project VA:figure2.jpg

    Meredith Clement, MD, Infectious Diseases, Duke University Medical Center, Durham, NC, Amr Hammouda, MD, Duke University Medical Center, na, NC, Lawrence Park, PhD, Infectious Diseases, Durham VA Medical Center, Durham, NC; Medicine, Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, Arlene C. Seña, MD, MPH, Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC and Maria Joyce, MD, Durham Va Medical Center, Durham, NC

    Disclosures:

    M. Clement, UpToDate: Section Author , Licensing agreement or royalty

    A. Hammouda, None

    L. Park, None

    A. C. Seña, None

    M. Joyce, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.