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Kelley Bemis

Kelley Bemis. CDC/CSTE Applied Epidemiology Fellowship STD Control Program Connecticut Department of Public Health k elley.bemis@ct.gov. Use of automated testing in syphilis diagnosis and its impact on surveillance – Connecticut , 2010. Background.

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Kelley Bemis

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  1. Kelley Bemis CDC/CSTE Applied Epidemiology Fellowship STD Control Program Connecticut Department of Public Health kelley.bemis@ct.gov Use of automated testing in syphilis diagnosis and its impact on surveillance –Connecticut, 2010

  2. Background National Plan to Eliminate Syphilis implemented Graph: Together We Can SEE: The National Plan to Eliminate Syphilis, CDC, 2006

  3. National elimination plan reframed Primary and Secondary Syphilis Cases - 2002 - 2010

  4. Crucial for syphilis elimination • Identify infectious patients (laboratory confirmed) for partner notification • Identify outbreaks and target interventions • Mainly laboratory reporting • Labs must report positive tests in 48 hours • Mail reports to DPH Syphilis Surveillance Understanding laboratory testing is necessary for accurate surveillance

  5. Usually two serologic tests • Non-specific test • e.g. rapid plasma reagin test (RPR), Venereal Disease Research Laboratory test (VDRL) • Detects antibodies against host lipoidal antigens • Indicates active infection • Inexpensive, simple, manual • Specific test • e.g. T. pallidum particle agglutination (TPPA), fluorescent treponemal antibody absorption assay (FTA-ABS) • Detects antibodies against treponemal antigens • Indicates infection, past or present Syphilis Diagnosis

  6. Non-specific test (RPR or VDRL) - + Specific test (TPPA or FTA-ABS) Syphilis unlikely - + Syphilis Syphilis unlikely Traditional Screening Algorithm

  7. One positive doesn’t confirm infection • Surveillance must monitor for two positives • Non-specific titers vary with age and stage of infection • Surveillance must consider past test results and likelihood of infectiousness Positive test ≠ Active infection Challenge for Surveillance #1

  8. Challenge for Surveillance #2 A shift in testing paradigm: Automated treponemal tests for screening • Treponemal EIAs and CIAs gaining popularity • More expensive but less manual labor needed • Still can’t distinguish between active and past infection Photo credit: Reverse Sequence Syphilis Screening Webinar, CDC, 2011

  9. Reverse Sequence Screening Algorithm EIA or CIA - + Syphilis unlikely Non-specific test (RPR or VDRL) Not identified with traditional algorithm - + Syphilis Specific test (TPPA) False positive EIA or CIA Previously treated syphilis Early primary syphilis - + Syphilis unlikely (or do another specific test) Syphilis (old or new)

  10. Challenge for Surveillance #2 • Increased testing volume • New questions for surveillance • How should EIAs and CIAs be reported? • Should discordant results be investigated? • Increased DPH workload

  11. To conduct a laboratory-focused evaluation of syphilis surveillance in Connecticut • Determine type and volume of syphilis testing performed by Connecticut laboratories • Determine if current surveillance procedures adequately monitors reported tests for infectious cases Objectives

  12. Methods, Part 1 • Laboratory Survey • Web survey emailed to all hospital and commercial labs in Connecticut (n=30) • Number of tests performed in 2010 • Testing algorithm • Reporting practices • Responses analyzed with descriptive statistics

  13. Methods, Part 2 • Laboratory Audit • Requested records from two commercial laboratories • All patients with a positive test in 2010 • Compared against records in state’s surveillance database • Investigated selection of tests missing from state’s database

  14. Laboratory Survey Results • 30 of 30 (100%) labs completed the survey • 28 of 30 (93%) perform syphilis testing • Over 196,700 screening tests performed in 2010

  15. Uptake of Automated Tests

  16. Referring Samples is Common

  17. Reporting Results

  18. Laboratory Audit Results • Lab A • Screens with a VDRL • Confirms with a FTA-ABS • RPR and FTA-ABS reported • 693 (56%) of 1241 positive reportable tests were not in the state’s database • Lab B • Screens with an EIA • Confirms all +’s with RPR and TPPA • RPR and TPPA reported • 372 (29%) of 1299 positive reportable tests were not in the state’s database

  19. Laboratory Audit Results • Small sample of missing tests investigated from both labs • Lab A • Random sample (n=35 patients) representing different months, tests, and titers • Lab B • All patients with both RPR and TPPA missing (n=13) • Most patients did not merit field investigation • We concluded that entry into state database is not consistent for these tests

  20. Conclusions • Uptake of automated tests is moderate, but increasing • Automated testing algorithms are variable • Referring specimens is common • Labs do not always report both types of tests used for diagnosis • Standard protocols for entering lab tests do not exist or are not enforced

  21. Recommendations • Create protocols for entering tests into the surveillance database • All non-specific tests are entered • Treponemal results may be entered only once • Negative tests will be entered if reported

  22. Recommendations • Establish provisional procedures for monitoring EIA/CIA’s and discordant results • EIA/CIA’s do not need to be reported unless a manual treponemal test was not performed • Discordant results will not be investigated

  23. Recommendations • Offer training on interpretation of EIA/CIA’s • Internal meetings with DPH Disease Intervention Specialists (DIS) • Newsletters to local health epidemiologists and clinicians

  24. Recommendations • Offer training on reporting requirements to laboratories • Newsletter to Laboratory Response Network

  25. Acknowledgments • Virginia Kristie, MT ASCP • Mark Lobato, MD • Lynn Sosa, MD • Connecticut laboratories This study was supported in part by an appointment to the Applied Epidemiology Fellowship Program administered by the Council of State and Territorial Epidemiologists (CSTE) and funded by the Centers for Disease Control and Prevention (CDC) Cooperative Agreement Number 5U38HM000414.

  26. Extra Slides

  27. Reporting of Referral Samples • From the OLC-15 Reporting Form: • From the Public Health Code:

  28. Test Sensitivity and Specificity Credit: Seña, A.C., White, B.L. & Sparling, P.F. Novel Treponemapallidum Serologic Tests: A Paradigm Shift in Syphilis Screening for the 21st Century. CID 51, 700-708 (2010).

  29. EIA/CIA Algorithms in Connecticut RPR - + - + + + EIA & TPPA TPPA RPR EIA & EIA x2 CIA RPR TPPA CIA RPR

  30. Sero-reactivity in Syphilis Tests Credit: Peeling et al. / Bulletin of the World Health Organization / 2004 / Vol. 82 / No. 6 via CDC Reverse Sequence Screening Webinar

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