key: cord-0867819-4qrkquyx authors: Peacock, W. Frank; Soto‐Ruiz, Karina M.; House, Stacey L.; Cannon, Chad M.; Headden, Gary; Tiffany, Brian; Motov, Sergey; Merchant‐Borna, Kian; Chang, Anna Marie; Pearson, Claire; Patterson, Brian W.; Jones, Alan E.; Miller, Joseph; Varon, Joseph; Bastani, Aveh; Clark, Carol; Rafique, Zubaid; Kea, Bory; Eppensteiner, John; Williams, James M.; Mahler, Simon A.; Driver, Brian E.; Hendry, Phyllis; Quackenbush, Eugenia; Robinson, David; Schrock, Jon W.; D'Etienne, James P.; Hogan, Christopher J.; Osborne, Anwar; Riviello, Ralph; Young, Stephen title: Utility of COVID‐19 antigen testing in the emergency department date: 2022-01-15 journal: J Am Coll Emerg Physicians Open DOI: 10.1002/emp2.12605 sha: af4b8d0dbc0c5ef2a20ffd0bb4f635a86cbfc68f doc_id: 867819 cord_uid: 4qrkquyx BACKGROUND: The BinaxNOW coronavirus disease 2019 (COVID‐19) Ag Card test (Abbott Diagnostics Scarborough, Inc.) is a lateral flow immunochromatographic point‐of‐care test for the qualitative detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) nucleocapsid protein antigen. It provides results from nasal swabs in 15 minutes. Our purpose was to determine its sensitivity and specificity for a COVID‐19 diagnosis. METHODS: Eligible patients had symptoms of COVID‐19 or suspected exposure. After consent, 2 nasal swabs were collected; 1 was tested using the Abbott RealTime SARS‐CoV‐2 (ie, the gold standard polymerase chain reaction test) and the second run on the BinaxNOW point of care platform by emergency department staff. RESULTS: From July 20 to October 28, 2020, 767 patients were enrolled, of which 735 had evaluable samples. Their mean (SD) age was 46.8 (16.6) years, and 422 (57.4%) were women. A total of 623 (84.8%) patients had COVID‐19 symptoms, most commonly shortness of breath (n = 404; 55.0%), cough (n = 314; 42.7%), and fever (n = 253; 34.4%). Although 460 (62.6%) had symptoms ≤7 days, the mean (SD) time since symptom onset was 8.1 (14.0) days. Positive tests occurred in 173 (23.5%) and 141 (19.2%) with the gold standard versus BinaxNOW test, respectively. Those with symptoms >2 weeks had a positive test rate roughly half of those with earlier presentations. In patients with symptoms ≤7 days, the sensitivity, specificity, and negative and positive predictive values for the BinaxNOW test were 84.6%, 98.5%, 94.9%, and 95.2%, respectively. CONCLUSIONS: The BinaxNOW point‐of‐care test has good sensitivity and excellent specificity for the detection of COVID‐19. We recommend using the BinasNOW for patients with symptoms up to 2 weeks. Although specific dates vary per different reports, 1 in Thailand on January 13, 2020. On January 20, 2020, the Centers for Disease Control and Prevention (CDC) confirmed the first US case. 3 Ten days later, the WHO declared a global health emergency, and coronavirus disease 2019 (COVID-19) was declared a pandemic on March 11, 2020. 4 As of August 1, 2021, this pandemic has spread to >200 countries, areas, or territories across the world, 5 with an estimated 197 million cases and 4.2 million deaths. A key aspect in controlling the spread is the need for accurate and rapid COVID-19 testing. Molecular testing, as currently employed, is focused on symptomatic individuals and captures only a portion of those who are contagious. Based on CDC estimates, 6 40% of infections are asymptomatic, and the percentage of transmission occurring before symptom onset is 50%. Thus, these asymptomatic individuals may unknowingly infect others with whom they come into contact. Laboratory-based reverse transcriptase (RT) polymerase chain reac- This was a prospective (defined as the data were gathered before the gold standard diagnosis was known), institutional review board- After informed consent and collection of the gold standard nasopharyngeal swab, research staff collected 2 nasal swabs from each patient. One nasal swab was tested immediately (within 10 minutes) using the BinaxNOW COVID-19 Ag test without elution into viral transport media (VTM). To perform the test, 6 drops of extraction reagent were added to the top hole of the swab well from a dropper bottle. The patient's nasal sample swab was then inserted into the test card through the bottom hole of the swab well and firmly pushed upward until the swab tip was visible through the top hole. Next, the swab was rotated 3 times and the card was closed, bringing the extracted sample into contact with the test strip. Test results were interpreted visually at 15 minutes based on the determination of the presence or absence of visually detectable pink/purple-colored lines (with no allowance for a gray zone), and results were recorded using photographs. The second nasal swab was placed in VTM and stored at −2 • C to −8 • C until shipped to the core lab. The order of nasal swab collection was randomized according to subject identification (ID) number. For those with an even-numbered subject ID, the first nasal swab collected was placed in the BinaxNOW device and the other swab was eluted into VTM. For patients with an odd-numbered subject ID, the opposite sequence occurred. Nasal swab sample collection was performed using gentle rotation, with the swab pushed into the nostril until resistance was met at the level of the turbinate (<1 in. into the nostril). The swab was then rotated several times against the nasal wall, then slowly removed, and collection was repeated using the same swab in the opposite nostril. The same process was repeated with a second swab; however, the samples were obtained in the opposite nare order than the first swab. Eluted VTM nasopharyngeal samples were tested at the core laboratory, blinded to the BinaxNOW results, on the Abbott RealTime SARS-CoV-2 platform (Abbott Diagnostics) provided by the sponsor. All reference testing was performed according to product instructions. Note: Data are provided as n (%). Study enrollment was planned to continue until 120 patients symptomatic for ≤7 days and positive for COVID-19 by the reference method were identified from an estimated 2200 patients. Planned data analysis was for positive and negative agreement, as well as sensitivity and specificity, between the reference standard and the BinaxNOW assay for a diagnosis of SARS-CoV-2 infection. Alternative diagnoses were not recorded nor adjudicated. An interim analysis was conducted after 30 reference positives were enrolled and used for an FDA Emergency Use Authorization (EUA) submission (which was approved). Finally, operation and ease of results interpretation of the BinaxNOW COVID-19 Ag testing was evaluated by a questionnaire completed by the staff who performed the test (Table 1 ). From July 20 to October 28, 2020, 767 patients were enrolled; of these, 32 (4.2%) were considered unevaluable and were excluded from the analysis. were <8 days and declined thereafter (see Table 2 ). Specificity was con- Finally, the ease of operations and interpretation of the results questionnaire (Table 1) was returned by 67 physicians, nurses, and research associates. The majority of answers regarding the ease of use, instructions, and interpretation of the BinaxNOW platform were all "strongly agree," except for the question regarding needing help on first-time use, for which only 25% "agreed." Our study is not without limitations. Whether similar results could be obtained by laypeople using this assay in different environments is unclear. In addition, the population studied was a convenience sample of ED patients, and therefore a sample bias may have occurred. Finally, this study did not evaluate this assay's performance with newly arising variants; whether it will perform equally with different variants is unknown. It should be noted that the enrollment rate per site may be considered low. This is because at the time of the pandemic that this study was performed, many EDs had simply furloughed their research staff to protect them from COVID-19, thereby allowing only essential clinical staff into their departments. Thus, to gather these critical data required essentially volunteer research staff, who did so at significant personal risk to enroll at each institution, which did slow the process. We found that nasal testing using the BinaxNOW point-of-care assay provides Although the BinaxNOW test has a lower sensitivity than the Abbott RealTime SARS-CoV-2 test, it has excellent specificity (98%) from day 1 to beyond 14 days of symptoms, allows rapid point-ofcare testing, provides a result that can be obtained by a nonlaboratory technician, and has better patient tolerability than a nasopharyngeal test. These features may provide improved identification of individuals infected with SARS-CoV-2 and in those at risk by virtue of exposure to known infected individuals. Application of this strategy may represent another tool to help contain the SARS-CoV-2 pandemic. Each author's institution received financial support for the performance of the study. Hajj Hussein I. 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