abbott rapid covid test false positive rate abbott rapid covid test false positive rate

Virus was cultured from 96 of 274 (35.0%) specimens, including 85 (57.8%) of 147 with concordant antigen and real-time RT-PCR positive results, 11 (8.9%) of 124 with false-negative antigen test results, and none of three with false-positive antigen test results. . Persons who know their positive test result within 1530 minutes can isolate sooner, and contact tracing can be initiated sooner and be more effective than if a test result is returned days later. For cultures, 200 L of patient specimen was diluted 1:1 with diluent containing 0.75% bovine serum albumin, and 50 L was added to 8 replicate wells in a 96-well plate containing confluent Vero-81 cells at 37C with 5% CO2. The other is a PCR test, in which samples are sent away for analysis in a lab. Among 127 rRT-PCRpositive specimens, the 55 with paired BinaxNOW-positive results had a lower mean cycle threshold than the 72 with paired BinaxNOW-negative results (17.8 vs. 28.5; p<0.001). The number of rRT-PCRpositive results in each round ranged from 98 (round 1) to 0 (round 4) (Table 2). A total of 342 different staff participated in testing rounds 1 through 6. Customers can self-administer the. While the chance of a false positive on a rapid test is low, it could mean the virus is less prevalent. The site is secure. During this period Canada reported roughly 1.7 million confirmed cases of COVID in a population of 38 million (4.5% of the population). Figure 2. Ford previously said launching the platform with the COVID-19 test "helped jumpstart demand.". JN, Proctor Among the 224 specimens undergoing viral culture that were analyzed with the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel for detection of SARS-CoV-2, median Ct values** were significantly higher for specimens with false-negative BinaxNOW antigen test results, indicating lower viral RNA levels than in those with concordant positive results (33.9 versus 22.0 in specimens from symptomatic persons [p<0.001] and 33.9 versus 22.5 in specimens from asymptomatic persons [p<0.001]) (Figure). Cummings, C. Hanson, M.K. That said, if your rapid test gives a positive result, you should assume you probably have COVID and isolate until you follow up with another type of test, like PCR. Message not sent. Moghadas SM, Fitzpatrick MC, Sah P, et al. Saving Lives, Protecting People, Centers for Disease Control and Prevention, Atlanta, Georgia, USA (K. Surasi), California Department of Public Health, Richmond, California, USA (K. Surasi, K.J. The Powerful Link Between Connectivity and MedTech Innovation, FDA authorizes first at-home flu-COVID-19 combination test days after its developer files for bankruptcy, Henry Schein Q4 profit drops, hurt by falling sales of COVID test kits, PPE, Baxter, Abbott, Thermo Fisher among medtech firms cutting jobs on supply issues, slide in testing, Thermo Fisher cuts additional 230 jobs in California. T, Nishihara Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. Questions or messages regarding errors in formatting should be addressed to JAMA. The rapid antigen test is generally very accurate, and certainly worth taking if you have any reason to think you might have Covid-19. These workplaces might benefit from effective rapid antigen tests that enable employers to quickly identify persons infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for isolation and to guide contact tracing, thereby reducing workplace transmission. 2023 American Medical Association. Subscribe to MedTech Dive for top news, trends & analysis, The free newsletter covering the top industry headlines, Viz.ai Announces Agreement with Bristol Myers Squibb to Enable Earlier Detection and Managemen, AVer to Showcase Connected Health Solutions at ATA 2023 Annual Conference and Expo, Equiva Partners with Infiniti Mobile to Advance Health Equity Via Newly Unveiled Affordable Co, Vivera Welcomes Former FDA Investigator Dennis Moore as Regulatory and Compliance Advisor, By signing up to receive our newsletter, you agree to our. More complete paired-testing data could have provided better insight as to the usefulness of rapid antigen testing when used for the entire duration of an outbreak. Abbott says it is making tens of millions of BinaxNow tests per month. Second, participants might have inadvertently reported common nonspecific symptoms as COVID-19compatible symptoms. Compared with real-time RT-PCR testing, the BinaxNOW antigen test had a sensitivity of 64.2% for specimens from symptomatic persons and 35.8% for specimens from asymptomatic persons, with near 100% specificity in specimens from both groups. Approximately one third (31.4%) of participants identified as Hispanic or Latino, and three quarters (75.1%) identified as White. All Rights Reserved, Challenges in Clinical Electrocardiography, Clinical Implications of Basic Neuroscience, Health Care Economics, Insurance, Payment, Scientific Discovery and the Future of Medicine. positives observed were attributable to manufacturing issues, as suggested by the authors. 552a; 44 U.S.C. Centers for Disease Control and Prevention. Sect. Additional rounds of testing were needed to monitor ongoing transmission and determine when the outbreak had ended. In addition, this activity was conducted as part of a COVID-19 project determined to be nonresearch by the California Health and Human Services Agencys Committee for the Protection of Human Subjects. Cookies used to make website functionality more relevant to you. Saving Lives, Protecting People, https://www.biorxiv.org/content/10.1101/2020.03.02.972935v1, https://cdn.ymaws.com/www.cste.org/resource/resmgr/ps/positionstatement2020/Interim-20-ID-02_COVID-19.pdf, https://www.cdc.gov/coronavirus/2019-ncov/lab/faqs.html#Interpreting-Results-of-Diagnostic-Tests, https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html, https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html, https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/vitro-diagnostics-euas, https://www.cdc.gov/coronavirus/2019-ncov/php/open-america/expanded-screening-testing.html, https://www.fda.gov/media/141570/download, https://www.fda.gov/media/137120/download, Centers for Disease Control and Prevention, U.S. Department of Health & Human Services. In this instance, it is recommended to . CRO. Our comparison supports immediate isolation for BinaxNOW-positive persons and confirmatory testing for negative persons. All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. The PPA of BinaxNOW was 43.0% and the NPV was 89.9%. Public health departments are implementing various strategies to reduce or prevent SARS-CoV-2 transmission, including expanded screening testing for asymptomatic persons (3). To evaluate the performance of the BinaxNOW rapid antigen test, it was used along with real-time reverse transcriptionpolymerase chain reaction (RT-PCR) testing to analyze 3,419 paired specimens collected from persons aged 10 years at two community testing sites in Pima County, Arizona, during November 317, 2020. 2021;27(11):2761-2767. https://doi.org/10.3201/eid2711.211449. BinaxNOW COVID-19 Ag card (PN 195000)instructions for use. Staff who tested positive by either BinaxNOW or rRT-PCR were isolated and excluded from further testing. Rapid antigen tests have received Food and Drug Administration (FDA) Emergency Use Authorization (EUA) for use in symptomatic persons (2), but data are lacking on test performance in asymptomatic persons to inform expanded screening testing to rapidly identify and isolate infected persons (3). Our rating: False. Abbreviation: COVID-19=coronavirus disease 2019. How many of the documented cases of COVID among employees were detected in the screening program, i.e. The Alinity m Resp-4-Plex AMP Kit is only authorized for use in laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) to perform moderate or high complexity tests. It is incorrect to refer to all positive rapid antigen test screens in which a PCR test, taken at about the same time, was negative, as "false positive" results. * Specimens were used to perform a limiting-dilution inoculation of Vero CCL-81 cells, and cultures showing evidence of cytopathic effect were tested by real-time RT-PCR for the presence of SARS-CoV-2 RNA. However, the results reported by Haage et al. The NYU researchers conducted a study involving 101 patients receiving emergency COVID-19 care through the system's Tisch Hospital. and/or the original MMWR paper copy for printable versions of official text, figures, and tables. Among specimens with positive viral culture, the sensitivity of the BinaxNOW antigen test compared with real-time RT-PCR in specimens from symptomatic participants was 92.6% (95% CI=83.7%97.6%) and in those from asymptomatic participants was 78.6% (95% CI=59.1%91.7%). Concept and design: Goldfarb, Agrawal, Sennik, Stein, Rosella. Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data. Multicenter postimplementation assessment of the positive predictive value of SARS-CoV-2 antigen-based point-of-care tests used for screening of asymptomatic continuing care staff. Viral replication in these specimens was defined as a decrease in Ct over the culture period. Performance characteristics of a rapid severe acute respiratory syndrome coronavirus 2 antigen detection assay at a public plaza testing site in San Francisco. Abbott Park, IL: Abbott; 2020. MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services. The study, which was pre-published on bioRxiv and has not been peer reviewed, suggested that Abbott's test produced false negative results for almost half of the positive samples. All data collected before June 26 and presumptive positive screen results and PCR test results reported before September 15 were externally verified through an audit process by participant organizations. Sect. Rapid antigen tests, such as the Abbott BinaxNOW COVID-19 Ag Card (BinaxNOW), offer results more rapidly (approximately 1530 minutes) and at a lower cost than do highly sensitive nucleic acid amplification tests (NAATs) (1). In the setting of a nonhealthcare workplace outbreak of COVID-19 with high attack rate (62.3%), we found that BinaxNOW was a useful adjunct to rRT-PCR testing. The FDA first gave emergency use authorization for Abbott Labs ' rapid COVID-19 test for at-home, over-the-counter and non-prescription use in March. . It's also molecular-based, so it's looking for genetic material from the virus in the mucus and infected cells in the sample from the patient. Testing for COVID-19. Surasi K, Cummings KJ, Hanson C, et al. Thank you for taking the time to confirm your preferences. Although the sensitivity of the BinaxNOW antigen test to detect infection was lower compared with real-time RT-PCR, it was relatively high among specimens with positive viral culture, which might reflect better performance for detecting infection in a person with infectious virus present. Screening results were recorded, including a deidentified record identifier, the place of employment, the test, and (optionally) the lot number. Positive viral culture is further evidence of the presence of infectious virus, so these findings might indicate that some BinaxNOW false-negative participants were not infectious at the time of specimen collection (i.e., they had low viral RNA load at the beginning or end of their infection trajectory) (12). Among all paired testing rounds with rRT-PCR, BinaxNOW produced these results when rRT-PCR tests with Ct <37 were considered positive: PPA, 43.3% (95% CI34.6%52.4%); NPA, 100% (95% CI99.4%100.0%); PPV, 100.0% (95% CI93.5%100.0%); and NPV, 89.9% (95% CI87.5%92.0%). We are talking to Dr. Hanan Balkhy today, who's going to explain testing for COVID-19. far too serious to allow misleading or faulty tests to be distributed. The first mass testing dates (round 0) only used rRT-PCR testing, so no comparison with BinaxNOW was possible. BinaxNOW showed NPA and PPV of 100%. After 1 h, the inoculum was removed and 200 L of minimum essential medium containing 5% fetal bovine serum and antibiotics was added to each well. Instead of taking hours . A box containing a 5-minute test for COVID-19 from Abbott Laboratories is pictured during the daily briefing on the novel coronavirus, COVID-19, in the Rose Garden of the White House on March 30. FDA used the warning to make two recommendations to users of Alinity tests. Corresponding author: Jessica L. Prince-Guerra, yov0@cdc.gov. 241(d); 5 U.S.C. ** Ct values from the N1 viral nucleocapsid protein gene region from real-time RT-PCR were compared only for specimens that were analyzed with the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel for detection of SARS-CoV-2. The PCR tests identified an additional 14 students who were positive for COVID-19; they were moved to isolation. Sensitivity was higher for culture-positive specimens (92.6% and 78.6% for those from symptomatic and asymptomatic persons, respectively); however, some antigen test-negative specimens had culturable virus. Department of Health and Human Services. Of those culture-positive specimens, 45 (88.2%) were BinaxNOW-positive (Table 4; Figure 2). So how common are false positive rapid COVID-19 tests? The Abbott ID Now Rapid Molecular Test for COVID-19 is the first in-house lab testing available . https://www.cdc.gov/coronavirus/2019-ncov/lab/faqs.html#Interpreting-Results-of-Diagnostic-Tests. If a test result was positive, the patient was immediately referred for a confirmatory polymerase chain reaction (PCR) test to be completed within 24 hours. Even a faint line next to the word "sample" on the test card is a positive result. provided as a service to MMWR readers and do not constitute or imply Administrative, technical, or material support: Gans, Goldfarb, Agrawal, Sennik. Performance and implementation evaluation of the Abbott BinaxNOW rapid antigen test in a high-throughput drive-through community testing site in Massachusetts. Curative is among the companies to adopt the platform. Kristen Garcia, Wenli Zhou, Morgan Ross, Lyndsay Wagner, Katherine Collins, Shelby Legendre, Christopher Johnson, Paradigm Laboratories, Tucson, Arizona; Spencer Graves, Pima County Health Department, Tuscon, Arizona; Anastasia Litvintseva, Dennis A. Bagarozzi, Jr., David James Petway, Jr., CDC. et al. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Morris, M. Salas, R. Thilakaratne, C. Stainken, D.A. With the ability to identify batch issues within 24 hours, workers could return to work, problematic test batches could be discarded, and the public health authorities and manufacturer could be informed. part 56; 42 U.S.C. Numerous biological (e.g., individual antibody status and specific sequence of the virus) and environmental (e.g., storage conditions and number of freeze-thaw cycles) variables can affect the sensitivity and outcome of viral culture. Over this period, Canada experienced 2 significant Delta variantdriven waves from March to June and August to October. A first swab specimen was used for onsite BinaxNOW testing; a second swab specimen was placed in viral transport medium and chilled on ice packs before transport to the CDPH laboratory for rRT-PCR testing 2472 hours after collection. Performance was better among symptomatic persons, specimens with cycle threshold (Ct) <30 (suggestive of higher viral loads), and specimens with positive viral cultures (38). Testing among symptomatic participants indicated the following for the BinaxNOW antigen test (with real-time RT-PCR as the standard): sensitivity, 64.2%; specificity, 100%; PPV, 100%; and NPV, 91.2% (Table 2); among asymptomatic persons, sensitivity was 35.8%; specificity, 99.8%; PPV, 91.7%; and NPV, 96.9%. The risk of false-negative or false-positive test results depends on the type and sensitivity of the COVID-19 diagnostic test, thoroughness of the sample collection, and accuracy of the lab analysis. Results from real-time RT-PCR and the BinaxNOW antigen test were compared to evaluate sensitivity, specificity, negative predictive value (NPV), and PPV. The overall rate of false-positive results among the total rapid antigen test screens for SARS-CoV-2 was very low, consistent with other, smaller studies.3 The cluster of false-positive results from 1 batch was likely the result of manufacturing issues rather than implementation. Keywords: Abbott ID Now; COVID-19; SARS-CoV-2; nasopharyngeal and nasal swabs; validation. Cycle threshold (Ct) values from real-time RT-PCR were compared using a Mann-Whitney U Test; 95% confidence intervals (CIs) were calculated using the exact binomial method. The FDA recommends that clinical laboratory staff and health care providers: The FDA issued an Emergency Use Authorization (EUA) to permit emergency use of the Alinity m SARS-CoV-2 AMP test on May 11, 2020 and granted revisions to the EUA with the most recent revision granted in August 2021. In this evaluation, using real-time RT-PCR as the standard, the sensitivity of the BinaxNOW antigen test was lower among specimens from asymptomatic persons (35.8%) than among specimens from symptomatic persons (64.2%). References to non-CDC sites on the Internet are There were 903408 rapid antigen tests conducted for 537 workplaces, with 1322 positive results (0.15%), of which 1103 had PCR information. Despite the limitations of interpreting culture-negative specimens, a positive viral culture is strong evidence for the presence of infectious virus. Letters to Health Care Providers, Recalls, Market Withdrawals and Safety Alerts, Potential for False Positive Results with Abbott Molecular Inc. Alinity m SARS-CoV-2 AMP and Alinity m Resp-4-Plex AMP Kits - Letter to Clinical Laboratory Staff and Health Care Providers, MedWatch, the FDA Safety Information and Adverse Event Reporting program, Medical Device Reporting (MDR) regulations, FDA's user facility reporting requirements. See, Voluntary reports can be submitted through, Generally, as specified in a test's EUA, device manufacturers must comply with the applicable, Health care personnel employed by facilities that are subject to the. Fierce Biotech. T, Schildgen Princeton, NJ: Fosun Pharma; 2020. AlexanderHarmon,BS; CelinaChang,BS; NolSalcedo,MS; BrenaSena,MPH; Bobby BrookeHerrera,PhD; IreneBosch,PhD; Laura E.Holberger,PhD, Joshua S.Gans,PhD; AviGoldfarb,PhD; LauraRosella,PhD. This conversion might result in character translation or format errors in the HTML version. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests. Thank you very much, Vismita. for symptomatic persons or for persons with a known COVID-19 exposure) a negative antigen test result should be confirmed by NAAT. False positives aren't common, but they can. CEO Robert Ford picked out the rollout of the analyzer as a driver of growth in Abbott's underlying diagnostics business in July. Because BinaxNOW testing was not performed for round 0, those 169 rRT-PCRpositive specimens were not included in this analysis. Surasi, K., Cummings, K. J., Hanson, C., Morris, M., Salas, M., Seftel, D.Wadford, D. A. A false-positive result was defined as a positive screen on a rapid antigen test and a subsequent negative confirmatory PCR. This low false-positive rate is consistent with results from Pilarowski et al. All specimens in viral transport medium were frozen at 70C within 12 hours of delivery to the laboratory. Coronavirus Disease 2019 (COVID-19): interim guidance for rapid antigen testing for SARS-CoV-2. This study was approved by the University of Toronto Research Ethics Board. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. o Contrast that with an asymptomatic patient, in whom the likelihood of COVID-19 . Viral culture was performed on 274 of 303 residual real-time RT-PCR specimens with positive results by either test (29 were not available for culture). NP swabs were stored in phosphate buffered saline at 39F (4C) and analyzed within 2448 hours by real-time RT-PCR using either the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel for detection of SARS-CoV-2 (5) (2,582 swabs) or the Fosun COVID-19 RT-PCR Detection Kit (6) (837 swabs). Positive Predictive Value depends upon prevalence of disease in community, Role of Rapid Antigen Detection Test (RADT) for Detection of SARS Cov-2 Variants. 2023 American Medical Association. Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices. Emerg Infect Dis. In contrast, our findings suggest that BinaxNOW negative results in an outbreak investigation should be confirmed with rRT-PCR, because false negatives do occur. The authors missed the opportunity to mention how this standard practice could have prevented this supposed occurrence of false positives. By continuing to use our site, or clicking "Continue," you are agreeing to our, Kretschmer Test + True Positive = 85 False Positive = 1 Positive Pred . Views equals page views plus PDF downloads. With serial BinaxNOW testing, some of the persons with discordant paired results could have tested positive with subsequent BinaxNOW testing. Additional Contributions: We thank Kyle Robinson, PhD, Devon Elke, HBSc, and Evgenia Gatov, MPH (all paid employees of CDL RSC, Toronto, Ontario, Canada), for assistance in collating the data. et al. Overflow into the wells of true negative samples that are positioned near positive samples in the assay tray could produce false positive results," FDA wrote in its alert. Critical revision of the manuscript for important intellectual content: Goldfarb, Agrawal, Sennik, Stein, Rosella. the date of publication. A 2021 study. Comment submitted successfully, thank you for your feedback. Suggested citation for this article: Prince-Guerra JL, Almendares O, Nolen LD, et al. False-positive results were matched to lot number and test manufacturer. It might also reflect a language barrier, because the question about symptoms was asked only in English by the administrative employee. A handful of rapid antigen tests are available without a prescription, including the Abbott BinaxNOW, the Ellume Covid-19 Home Test and the Quidel QuickVue At-Home Covid-19 Test. Of these, 278 false-positive results (60%) occurred in 2 workplaces 675 km apart run by different companies between September 25 and October 8, 2021. The agency is advising clinical laboratories and healthcare professionals to view any positive results delivered by Alinity as "presumptive.". BinaxNOW rapid antigen test results and viral culture results among 100 real-time reverse transcription PCRpositive specimens with cycle threshold <30 among staff at a horse racetrack, California, USA, NovemberDecember 2020. Of the 127 rRT-PCRpositive specimens, we attempted virus isolation and culture for all 100 specimens with Ct <30. Including testing performed in round 0 and results reported by outside laboratories from staff seeking testing on their own, the cumulative incidence over the course of the outbreak in the entire staff was 62.3% (351/563). The false-positive rate for a PCR test is close to zero, though. Silver Spring, MD: US Department of Health and Human Services, Food and Drug Administration; 2020. Initial data validation was completed at the point of collection. (5), which indicates that bands are scored as positive only if they extend across the full width of the strip, irrespective of the intensity of the band. Most staff identified as Hispanic (62.0%) (Table 1). Consider communicating to patients who received positive results using the Alinity m SARS-CoV-2 AMP and the Alinity m Resp-4-Plex AMP Kits, starting in June 2021, that they may have had a false positive test result. even in this symptomatic group, the false negative rate is less than 1 out of 50 negative tests. We take your privacy seriously. Evaluation of Abbott BinaxNOW rapid antigen test for SARS-CoV-2 infection at two community-based testing sitesPima County, Arizona, November 317, 2020. Accuracy: 84.6% for detecting covid-19 infections, 98.5% for correctly identifying covid-19 negatives This is the. Individuals presenting for molecular testing in two of seven lanes were offered the opportunity to also receive BinaxNOW testing. Medtech. Sunny Hostin and Ana Navarro were cleared to return to The View Monday after the co-hosts made a dramatic exit from the show on Friday. There are two types of rapid COVID-19 tests that detect the coronavirus. As described in Pilarowski et al. The kits can report false positives when wells in the assay reagent tray that contain positive samples overflow and contaminate neighboring specimens. After receiving reports of false results from its own test, Curative asked FDA to revoke its, Abbott first received FDA emergency use authorization for its Alinity m SARS-CoV-2 AMP test in May 2020. Wadford), Golden Gate Fields, Berkeley, California, USA (D. Seftel), City of Berkeley Public Health Officer Unit, Berkeley (L. Ortiz), Kaiser Permanente San Francisco Internal Medicine Residency Program, San Francisco, California, USA (C. Stainken). We performed rRT-PCR by using the ThermoFisher TaqPath COVID-19 Combo Kit, which targets 3 SARS-CoV-2 viral regions (nucleocapsid protein gene, spike protein gene, and open reading frame 1ab), and the Applied Biosystems 7500 Fast Dx Real-Time PCR Instrument (ThermoFisher Scientific), according to the manufacturers instructions. No potential conflicts of interest were disclosed. Welcome, Hanan. Previous studies of BinaxNOW compared with rRT-PCR have demonstrated a high negative percent agreement (NPA) (99.4%100%) but variable positive percent agreement (PPA) (52.5%89.0%). If 58% were confirmed there were 767 screen-detected cases of infection (6.6% of the study cohort). Workplace participation was voluntary. On the day of testing, a facility administrative employee conducted registration and collected demographic data, including self-reported race and ethnicity. In a clinical context, real-time RT-PCR provides the most sensitive assay to detect infection. For older positive test findings, dating back as far as June, FDA is advising users to consider telling the patient their result may have been false. This number conflicts with data previously collected from the racetrack physician as part of a prospective cohort drug trial on this same population which, out of an enrolled cohort of 113 BinaxNOW-positive staff, identified 60 (53%) persons who were symptomatic at the time of testing (14). Paired upper respiratory swabs were collected from 3,419 persons, including 1,458 (42.6%) from site A and 1,961 (57.4%) from site B (Table 1). We used the paired BinaxNOW and rRT-PCR results to calculate the BinaxNOW PPA, NPA, negative predictive value (NPV), and positive predictive value (PPV), using Ct <37 to define rRT-PCRpositive specimens. Effectiveness of Abbott BinaxNOW Rapid Antigen Test for Detection of SARS-CoV-2 Infections in Outbreak among Horse Racetrack Workers, California, USA. We found positive percent agreement was 43.3% (95% CI34.6%52.4%), negative percent agreement 100% (95% CI99.4%100%), positive predictive value 100% (95% CI93.5%100%), and negative predictive value 89.9% (95% CI87.5%92.0%). Original Publication Date: September 01, 2021, Table of Contents Volume 27, Number 11November 2021. The Wrong Way to Test Yourself for the Coronavirus. Among symptomatic participants, 113 (13.7%) received a positive BinaxNOW antigen test result, and 176 (21.3%) received a positive real-time RT-PCR test result. The prevalence of having SARS-CoV-2 real-time RT-PCR positive test results in this population was moderate (8.7% overall; 4.7% for asymptomatic participants); administering the test in a lower prevalence setting will likely result in a lower PPV. Among 11 participants with antigen-negative, real-time RT-PCRpositive specimens with positive viral culture, five were symptomatic and six asymptomatic. Cells were monitored for cytopathic effect. Curative. CDC is not responsible for the content Fierce Healthcare. Like BINAXNow, Flowflex is a lateral flow test. Effectiveness of Abbott BinaxNOW Rapid Antigen Test for Detection of SARS-CoV-2 Infections in Outbreak among Horse Racetrack Workers, California, USA. in long-term care facilities) should also receive confirmatory testing by NAAT (1). 241(d); 5 U.S.C. W, Negative BinaxNOW results were less concordant with rRT-PCR results. Both Hostin and Navarro, who are fully vaccinated against. Using real-time RT-PCR as the standard, four false-positive BinaxNOW antigen test results occurred, all among specimens from asymptomatic participants. We thank Lisa B. Hernandez, James Allard, Beimnet Taye, the California Department of Public Health Viral and Rickettsial Disease Laboratory staff, and the racetrack staff described in this report.