Use of PCR for Diagnosis of Group A Streptococcal Pharyngitis in the United States, 2011–2015

BACKGROUND: Although rapid antigen testing and culture are recommended for diagnosis of Group A Streptococcal pharyngitis in the US, polymerase chain reaction (PCR) tests are becoming more widely available. This study evaluated diagnosis and management of strep throat in the USA from 2011 to 2015, and the extent to which PCR and other diagnostic modalities were utilized. METHODS: A retrospective cohort analysis was performed using the 2011–2015 MarketScan Commercial and Medicare databases, covering over 200 million insured US individuals. Streptococcal sore throat, acute pharyngitis, or acute tonsillitis were defined using ICD9/10 diagnosis codes. Each strep throat event spanned a 2-week period from the index visit, with patient demographics and provider characteristics examined across five testing categories for strep throat: rapid test, rapid test with culture, other tests, PCR, and no test. Descriptive and multivariable statistics were used to identify potential predictors of testing type and antibiotic usage. RESULTS: 18.8 million strep throat events were identified in 11.6 million patients, and over 40% of strep throat events occurred in patients under 18 years of age. Overall, 43.0% had a rapid test only, 19.8% had rapid test and culture, 9.2% had other test combinations, and 0.1% had a PCR test done only. Over a quarter (27.9%) had no test. PCR testing usage in 2015 increased 3.5 times that of 2011 (0.06% vs. 0.27%) while rapid testing remained similar (43.0% vs. 44.8%). Over 75% of PCR testing occurred with office visits. Antibiotic use was significantly lower in patients receiving PCR tests (34.6%) or rapid tests with culture (31.3%) compared with those getting rapid testing only (53.4%) or no testing (57.1%). CONCLUSION: Use of gold standard diagnostic tests for Strep including rapid with confirmatory culture or PCR is associated with lower use of antibiotics. PCR testing nearly tripled between 2011 and 2015 but use remained low overall. Current guidelines for Group A Streptococcal pharyngitis and antibiotic stewardship initiatives should consider how to include recommendations on the use of PCR for the diagnosis of strep throat. DISCLOSURES: R. Luo, Roche: Employee, Salary; J. Sickler, Roche: Employee, Salary; F. Vahidnia, Roche: Employee, Salary; Y. C. Lee, Roche: Employee, Salary; B. Frogner, Roche: Consultant, Consulting fee; M. Thompson, Roche: Consultant, Consulting fee; Alere, Inc.: Grant Investigator, Research grant Phoresa, Inc.: Board Member and Shareholder, Shares