Reactor Grids for Prioritizing Syphilis Investigations: Are Primary Syphilis Cases Being Missed?

• Published in: Sexually transmitted diseases 2018-10, Vol.45 (10), p.648-654
• Main Authors: Cha, Susan, Matthias, James M, Rahman, Mohammad, Schillinger, Julia A, Furness, Bruce W, Pugsley, River A, Kidd, Sarah, Bernstein, Kyle T, Peterman, Thomas A
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age; Aged; Blood tests; Centers for Disease Control and Prevention (U.S.); Child; Child, Preschool; Computerization; Elderly men; Epidemiological Monitoring; Female; Gender; Humans; Infant; Infant, Newborn; Male; Medical equipment; Men; Middle Aged; Older people; Prioritizing; Public health; Reactors; Sexually transmitted diseases; STD; Surveillance; Syphilis; Syphilis - diagnosis; Syphilis - epidemiology; Syphilis Serodiagnosis - methods; Syphilis Serodiagnosis - standards; Syphilis, Latent - diagnosis; Syphilis, Latent - epidemiology; United States - epidemiology; Young Adult
• ISSN: 0148-5717; 1537-4521
• DOI: 10.1097/OLQ.0000000000000833

BACKGROUNDHealth departments prioritize investigations of reported reactive serologic tests based on age, sex, and titer using reactor grids. We wondered how reactor grids are used in different programs, and if administratively closing investigations of low-titer tests could lead to missed primary syphilis cases. METHODSWe obtained a convenience sample of reactor grids from 13 health departments. Interviews with staff from several jurisdictions described the role of grids in surveillance and intervention. From five jurisdictions, trends in reactive nontreponemal tests and syphilis cases over time (2006–2015) were assessed by sex, age, and titer. In addition, nationally-reported primary syphilis cases (2013–2015) were analyzed to determine what proportion had low titers (≤1:4) that might be administratively closed by grids without further investigation. RESULTSGrids and follow-up approaches varied widely. Health departments in the study received a total of 48,573–496,503 reactive serologies over a ten-year period (3,044–57,242 per year). In 2006–2015, the number of reactive serologies increased 37–169%. Increases were largely driven by tests for males although the ratios of tests per reported case remained stable over time. Almost one-quarter of reported primary syphilis had low titers that would be excluded by most grids. The number of potentially missed primary syphilis cases varied by sex and age with 41–54 year old males accounting for most. CONCLUSIONSReactor grids that close tests with low titers or from older individuals may miss some primary syphilis cases. Automatic, computerized record searches of all reactive serologic tests could help improve prioritization.