1. Assessment of De-Duplication Methods for Gonorrhea and Chlamydia Case Reports
Emily Weston, MPH
2016 Annual CSTE Meeting
Tip of the Infectious Disease Surveillance Disease Iceberg: Surveillance/Informatics Rapid Fire
Tuesday, June 21, 2016
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of STD Prevention

2. Methods
In 2015, STD surveillance programs completed an assessment of current surveillance practices
Reporting practices were reviewed for de-duplication of cases of chlamydia and gonorrhea separately, including:
the time period used to decide when a second positive test should be reported as a case AND
the method of de-duplication (e.g., automatic or manual)

3. Why did we ask about these surveillance practices?
Chlamydia and gonorrhea are the 2 most commonly reported conditions in the US
Both can be diagnosed with highly sensitive nucleic acid amplification tests (NAATs)
No guidance from CDC on the minimum amount of time between positive laboratory test results and when to report a new infection

4. Results
93% (54/58) of jurisdictions provided valid responses for the de-duplication questions
Reported time period for de-duplication of case data varied by jurisdiction and by pathogen
Sites reported a range (7-90 days) for de-duplication of gonorrhea and chlamydia case report data
Majority of jurisdictions reported using 30 days
31/54 (57%) jurisdictions for chlamydia
29/54 (54%) jurisdictions for gonorrhea

5. Results
Two jurisdictions had additional de-duplication rules for certain populations
different time periods for pregnant women and 30 days from treatment
Six jurisdictions reported different time periods for when de-duplication is performed for gonorrhea and chlamydia
Jurisdiction
Chlamydia De-duplication time frame (in days)
Gonorrhea De-duplication time frame
(in days)
Baltimore 30 15
Hawaii 60
Massachusetts 28 14
Minnesota 21
Individually reviewed
Virginia
Washington 7

6. Results
Jurisdictions were asked to describe de-duplication for the following at their jurisdiction:
Same test from multiple reporting sources (e.g., laboratory report and provider report)
Multiple tests diagnosing same infection (e.g., 2 laboratory reports on the same person in 1 week)
De-duplication methods varied across jurisdictions (n=54)
De-duplication method
Same test from multiple sources/reports
Multiple tests diagnosing the same infection
Automatic
26%
28%
Manual
24%
20%
Combination
31%
22%
Undeterminable

7. Outcomes Presented data to jurisdictions on quarterly CSTE call
Proposed algorithm for de-duplicating chlamydia and gonorrhea cases to jurisdictions

8. Is there evidence of re-infection*?
De-Duplication Methods Algorithm
Is there evidence of a prior infection that has already been reported as a case? No
Report as a new case
Yes
Did the previously reported infection have:
• a specimen collection date in the prior 30 days OR
• a documented treatment date in the prior 30 days No
Report as a new case
Yes
Is there evidence of re-infection*? No
De-duplicate laboratory report and
do not report as a case
Yes
Report as a new case
*Evidence of reinfection will require examination into various sources at each jurisdiction (e.g., partner services and management of partners, investigation into completion of antibiotic treatment)

9. Conclusions
Surveillance assessment allowed insight into current practices of jurisdictions regarding an important surveillance ‘best practice’ topic (i.e., de-duplicating cases)
Means and time period for de-duplication of cases varied by jurisdiction and by pathogen
Range 7-90 days; majority of jurisdictions use 30 days
To assist with performance, training, and improve surveillance practices, we proposed a standard timeframe in which cases should be de-duplicated
Developed website link for jurisdictions to reference tools for de-duplicating cases

10. Acknowledgements Elizabeth Torrone, PhD Hillard Weinstock, MD, MPH
Surveillance and Data Management Branch Team Members
CSTE Jurisdictions

11. References
Workowski KA, Bolan GA. Sexually Transmitted Diseases Treatment Guidelines, MMWR 2015;64(No. RR 3):
Papp JR, Schachter J, Gaydos CA, Van der Pol B. Recommendations for the Laboratory-Based Detection of Chlamydia trachomatis and Neisseria gonorrhoeae – MMWR 2014;63(No. RR-2):1-19.
Council of State and Territorial Epidemiologists (CSTE). Update to Public Health Reporting and National Notification for Gonorrhea. 13-ID-03. Atlanta: CSTE; Available from:
Council of State and Territorial Epidemiologists (CSTE). Public Health Reporting and National Notification for Infection Caused by Chlamydia trachomatis. 09-ID-08. Atlanta: CSTE; Available from:
Gaydos CA, Crotchfelt KA, Howell MR, Kralian S, Hauptman P, Quinn TC. Molecular amplification assays to detect chlamydial infections in urine specimens from high school female students and to monitor the persistance of chlamydial DNA after therapy. J Infect Dis 1998;177:417–24.
Workowski KA, Lampe MF, Wong KG, Watts MB, Stamm WE. Long-term eradication of Chlamydia trachomatis genital infection after antimicrobial therapy. JAMA 1993;270:2071–5.
Bachmann LH, Desmond RA, Stephens J, Hughes A, Hook EW III. Duration of persistence of gonococcal DNA detected by ligase chain reaction in men and women following recommended therapy for uncomplicated gonorrhea. J Clin Microbiol 2002;40:3596–601.

12. Questions?
For more information please contact Centers for Disease Control and Prevention
1600 Clifton Road NE, Atlanta, GA
Telephone: CDC-INFO ( )/TTY:
Visit: | Contact CDC at: CDC-INFO or
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of STD Prevention