1640. Pertussis Testing in the Department of Veterans Affairs, 2010–2018

BACKGROUND: Bordetella pertussis causes a highly contagious, nationally reportable respiratory illness resulting in violent coughing. Pertussis outbreaks continue despite an available vaccine. Appropriate pertussis testing depends on timing from the onset of symptoms. Culture testing within 2 weeks from symptom onset is gold standard, while PCR testing is reasonable up to 3–4 weeks and serology testing 2–12 weeks from symptom onset per CDC. We describe pertussis testing in the Department of Veterans Affairs (VA) from 2010–2018. METHODS: VA data sources were queried for all Bordetella pertussis tests (culture, DFA, IgA, IgG, IgM, and PCR) from January 2010 to December 2018. Data were compared across years. A random selection of 10 patient charts with both positive and negative test results for each type of testing were reviewed to determine timing from onset of symptoms to testing. RESULTS: From 2010 to 2018, 37,356 pertussis tests (28,174 unique patients) were performed in VA nationally. Increased testing occurred in 2012 (most recent peak year) and PCR testing increased in 2014 with introduction of multiplex panels. Otherwise testing was stable between years (Figure 1). Positive test results included culture 1/252 (0.4%), DFA 4/204 (2%), IgA 459/1,546 (29.7%), IgM 168/1,189 (14.1%), IgG 1,156/2,291 (50.4%), and PCR 47/31,847 (0.2%) (Figure 2). Total positive tests per year ranged from 161 in 2015 to 313 in 2012. Across the years, IgG was the most common positive test. In 37/60 (62%) charts reviewed, appropriate test was chosen based on duration of symptoms. 9/60 (15%) had no symptom duration documented and 14/60 (23%) did not have appropriate pertussis testing chosen based on symptom duration. DFA testing chart reviews were not included as there is no CDC recommendation for DFA testing in pertussis diagnosis. CONCLUSION: Number of pertussis-positive results remained stable despite increased testing, primarily from multiplex PCR testing. IgG, often a marker of immunity, was the most common test to be positive across the studied timeframe. In a small sampling of patients, about two-thirds received appropriate testing based on symptom duration. With the multitude of pertussis tests ordered, further education of clinicians on appropriate testing based on timing of symptoms is needed. [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.