Research Article Operator Influence on Blinded Diagnostic Accuracy of Point-of-Care Antigen Testing for Group A Streptococcal Pharyngitis Carla Penney, 1 Robert Porter, 1 Mary O’Brien, 2 and Peter Daley 1 1 Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL, Canada A1B 3V6 2 Newfoundland and Labrador Eastern Health, St. John’s, NL, Canada A1B 3V6 Correspondence should be addressed to Peter Daley; pkd336@mun.ca Received 5 April 2016; Revised 19 June 2016; Accepted 11 July 2016 Academic Editor: Nahuel Fittipaldi Copyright © 2016 Carla Penney et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Acute pharyngitis caused by Group A Streptococcus (GAS) is a common presentation to pediatric emergency departments (ED). Diagnosis with conventional throat culture requires 18–24 hours, which prevents point-of-care treatment decisions. Rapid antigen detection tests (RADT) are faster, but previous reports demonstrate signifcant operator infuence on performance. Objective. To measure operator infuence on the diagnostic accuracy of a RADT when performed by pediatric ED nurses and clinical microbiology laboratory technologists, using conventional culture as the reference standard. Methods. Children presenting to a pediatric ED with suspected acute pharyngitis were recruited. Tree pharyngeal swabs were collected at once. One swab was used to perform the RADT in the ED, and two were sent to the clinical microbiology laboratory for RADT and conventional culture testing. Results. Te RADT when performed by technologists compared to nurses had a 5.1% increased sensitivity (81.4% versus 76.3%) ( = 0.791) (95% CI for diference between technologists and nurses = −11% to +21%) but similar specifcity (97.7% versus 96.6%). Conclusion. Te performance of the RADT was similar between technologists and ED nurses, although adequate power was not achieved. RADT may be employed in the ED without clinically signifcant loss of sensitivity. 1. Introduction Acute pharyngitis is a common presentation to primary care physicians and pediatric ED, accounting for 6–8% of visits each year in high-income nations [1, 2]. While most cases of acute pharyngitis are viral in origin, 20–40% [1, 3] of cases are caused by Group A Streptococcus (GAS) infection. 60–70% of children presenting with acute pharyngitis will be prescribed an antibiotic [1, 4], suggesting that appropriate diagnostic testing is not always performed, and antimicrobial steward- ship could be improved. Considering the high prevalence, stewardship impact could be signifcant. Diferentiating between viral and GAS pharyngitis is difcult, with even the most experienced clinician being unable to discern the signs and symptoms reliably [3]. Clinical prediction rules (e.g., Centor criteria [5] and McIsaac score [6]) have been developed to aid clinicians in predicting GAS infection, but the performance of rules is not high enough to inform treatment without culture [2, 3, 7]. Te reference standard for diagnosing GAS pharyngitis is a throat swab cultured on selective agar. Culture has a sensitivity of approximately 90% to 95% and specifcity of approximately 99% [8] but requires 18–24 hours incubation, which prevents point-of-care treatment decisions and requires a second contact with the patient to provide results. Rapid antigen-detecting tests (RADT) for diagnosis of GAS demonstrate excellent specifcity (approximately 95%) but variable sensitivity (66%–99%) [3, 9]. Sensitivity is infuenced by disease severity, size of the bacterial inoculum obtained on the swab, and operator infuence on testing technique [3]. When nursing staf and laboratory technicians perform the same RADT, diagnostic performance of technol- ogists is signifcantly better, with a diference in sensitivity ranging from 14% to 34% between groups [10, 11]. Tis may be due to operator experience, compliance with the method when performing the test, experience in reading RADTs, or Hindawi Publishing Corporation Canadian Journal of Infectious Diseases and Medical Microbiology Volume 2016, Article ID 1710561, 4 pages http://dx.doi.org/10.1155/2016/1710561