News-Medical. Diagnostic accuracy of covid-19 rapid antigen tests with unsupervised self-sampling in people with symptoms in the omicron period: cross sectional study. Objective: We found no differences in test results overall nor in the RT-PCR test positive group between participants who completed the questionnaire within three hours and those who completed it later on. We use cookies to enhance your experience. Inconclusive represents a combination of tests that showed no control line, test tubes were dropped, and test result was difficult to interpret (eg, faint line). 2022 May;52(3):511-525. . On Monday, the FDA authorized the Flowflex test - made at ACON laboratories in Southern California. Only one of Australia's 23 approved at-home rapid antigen tests explicitly states it will detect Omicron, as the Therapeutic Goods Administration carries out a review of all tests to check how . technical support for your product directly (links go to external sites): Thank you for your interest in spreading the word about The BMJ. This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. Researchers found that the sensitivity of three rapid antigen tests -- the ability to correctly identify a true positive sample -- declined as Omicron became the dominant variant. The Flowflex COVID-19 Antigen Home Test, which the FDA authorized for emergency use on Oct. 4, gave a correct positive result 93% of the time and a correct negative result 100% of the time in. Retrieved on March 04, 2023 from https://www.news-medical.net/news/20211229/Rapid-antigen-tests-show-lower-sensitivity-for-Omicron-than-for-earlier-SARS-CoV-2-variants.aspx. Inconclusive represents a combination of tests that showed no control line, test tubes were dropped, and test result was difficult to interpret (eg, faint line). Individuals with a negative self-test result should adhere to general preventive measures because a false negative result cannot be ruled out. We previously showed that the sensitivity of the Roche/SD Biosensor (Roche Diagnostics) rapid antigen test with unsupervised nasal self-sampling was 78.5% in individuals with symptoms.7 Since the end of November 2021, however, the omicron variant of SARS-CoV-2 rapidly replaced the delta variant. The rapid antigen diagnostic tests studied were Flowflex (Acon Laboratories), MPBio (MP Biomedicals), and Clinitest (Siemens-Healthineers). Diagnostic accuracy of covid-19 rapid antigen tests with unsupervised self-sampling in people with symptoms in the omicron period: cross sectional study - September 16, 2022 Ewoud Schuit, assistant professor 1 2, Roderick P Venekamp, associate professor 1, Lotty Hooft, professor 1 2, Irene K Veldhuijzen, senior epidemiologist 3, The TGA is reviewing all COVID-19-specific laboratory antigen tests and rapid antigen tests (RATs), including point-of-care and self-tests, included in the Australian Register of Therapeutic Goods (ARTG). Flowflex is FDA Emergency Use Authorized (EUA) for self-testing without the need for a prescription. In this article, News-Medical talks to Sartorius about biosensing and bioprocessing in gene therapy, The emergence of a new SARS-CoV-2 VOC necessitates a study of its potential impact on diagnostic performance. Image Credit: Roman Zaeits / Shutterstock.com, https://www.medrxiv.org/content/10.1101/2021.12.18.21268018v1, Clec9A-RBD immunization could trigger robust and sustained systemic and mucosal immune responses against rapidly evolving SARS-CoV-2 variants, 25% of COVID-19 patients have lasting reduction in lung function, In-depth assessment of muscle biopsies in patients with long COVID, Study shows antibody-dependent SARS-CoV-2 transmission and pathogenesis, Rebounding of COVID-19 symptoms and viral load are common among untreated COVID-19 patients. Manufacturer Test name Sensitivity Cq 25 Cq >25- <30 Cq 30 Cq 17-36 1 Abbott Rapid Diagnostics Jena GmbH PanbioCOVID-19 Ag Rapid Test Device (NASOPHARYNGEAL) 100.0% 60.9% 0.0% 64.0% 2 ACON Biotech (Hangzhou) Co., Ltd Flowflex SARS-CoV-2-Antigenschnelltest (Nasopharynxtupfer) 94.1% 4.3% 0.0% 34.0% 3 Aesku Diagnostics GmbH Saurabh Chaturvedi is a freelance writer from Jaipur, India. This is especially common with Omicron, which according to a recent Imperial College London report is more than five times more likely to cause reinfection than the Delta variant. Before In two previous studies, however, we observed similar trends for the BD Veritor (Becton, Dickinson) and Roche/SD Biosensor rapid antigen tests with either professional or self-sampling.57 The lower sensitivities of rapid antigen tests in individuals with a previous infection might be explained by generally lower viral loads, with some individuals potentially carrying viral RNA in the absence of a productive infection (ie, no viral antigen production). Meanwhile, starting Saturday, private health insurers will be required to cover up to eight home COVID-19 tests per month under a policy President Joe Biden announced last month. Logically, a higher proportion of confirmatory testers (93% to 95%) than other testers (76% to 77%) had viral loads above the used viral load cut-off. The widely used Abbott BinaxNOW antigen coronavirus test can detect the majority of omicron cases in people who are carrying high levels of the virus, performing at a level similar to what was seen with previous variants, a new study found. Chan School of Public Health said. Individual participant data collected during the study will be available, after deidentification of all participants. The rise of the omicron coronavirus variant has put an increased focus on regular testing, but are rapid lateral flow tests the . Inconclusive represents a combination of tests that showed no control line, test tubes were dropped, and test result was difficult to interpret (eg, faint line). It can also be that earlier in the infection by BA.4 and BA.5, you dont produce enough of the SARS-CoV-2 protein, she added. Omicron replicates very fast, so you may become very infectious within hours, says Petersen. Additionally, the Del31-33 deletion is found in the Omicron nucleocapsid protein, along with another P13L mutation, which is present in some but not all Omicron sequences. It found that rapid tests detected 95% of infections in people with high viral loads. Brakenhoff TB, Franks B, Goodale BM, van de Wijgert J, Montes S, Veen D, Fredslund EK, Rispens T, Risch L, Dowling AV, Folarin AA, Bruijning P, Dobson R, Heikamp T, Klaver P, Cronin M, Grobbee DE; COVID-RED Consortium. In this interview, AZoM speaks to Rohan Thakur, the President of Life Science Mass Spectrometry at Bruker, about what the opportunities of the market are and how Bruker is planning on rising to the challenge. Published by BMJ. A rapid test checks for proteins from the coronavirus in the user's body, which means it is less accurate in the early or final stages of an infection, according to Bloomberg. Most analyses, apart from the time trend analyses, included data from the latter omicron period. In late 2021 in the Netherlands, the public debate about covid-19 included discussions about the sensitivity of self-testing using commercially available tests. Specificities were >92%, positive predictive values >94%, and negative predictive values >59% for all three rapid antigen tests in all analyses (table 2), with slightly higher specificities and positive predictive values for MPBio and Clinitest and higher negative predictive values for Flowflex. You no longer have to get a follow-up PCR test if you test positive on a lateral flow with no symptoms. A prospective, randomized, single-blinded, crossover trial to investigate the effect of a wearable device in addition to a daily symptom diary for the remote early detection of SARS-CoV-2 infections (COVID-RED): a structured summary of a study protocol for a randomized controlled trial. ES, RPV, and KGMM verified the underlying data. A table showing the Flowflex SARS-CoV-2 Antigen Rapid Test (Self-Testing) test which is not authorized by the FDA and the Flowflex COVID-19 Antigen Home Test which is authorized. We do not capture any email address. Original reporting and incisive analysis, direct from the Guardian every morning. The overall sensitivity of rapid antigen tests was 63%. Supplementary material 4 discusses the results for subgroup effects based on sex and age. Interventions: For how long do I have to swab my nostril? Previous studies, including our own studies, have shown that antigen tests require a higher viral load to show positivity than molecular tests such as RT-PCR.257 This was confirmed in the current study: the mean viral load in confirmatory testers was higher than in the non-confirmatory testers. According to national SARS-CoV-2 pathogen surveillance, during the study period the percentage of infections attributable to omicron increased from 29% (week 51 in 2021) to 99% (week 5 in 2022; >95% BA.1 variant).151617 From 12 January 2022 onwards, omicron accounted for >90% of infections. The main benefit of LFTs is they can be carried out quickly and easily at home, with a result in under 30 minutes, and that they dont need to be sent to a lab. Data from the FDA suggested that these at-home tests do detect the omicron variant but may have reduced sensitivity.. When the Omicron variant first emerged, . Flowflex antigen test detects COVID-19, including the Omicron variant, in just 15 minutes with 98.8% accuracy . Self-isolation for those who test positive but are asymptomatic begins from the day they take the test, not the day they receive a positive result as stated in an earlier version. The polymerase chain reaction test, or PCR test typically available at a hospital or a lab is usually more on the mark. Product contents: 5 Test Cassettes 5 Extraction Buffer Tubes 5 Waste Bags 5 Nasal Swabs Product Insert in both Traditional Chinese and English Evaluation of Antigen rapid test and PCR test to Omicron variant. Sensitivity. A faint positive lateral flow test result is shown in the image above Credit: Sun Online. The RT-PCR sampling method differed slightly across test sites; the Rotterdam and Tilburg sites used oropharyngeal and nasopharyngeal sampling and the Roosendaal site combined oropharyngeal and nasal sampling (see supplementary material 3). Conversely, the rapid antigen test result was not available to the laboratories that conducted the RT-PCR tests for the public health service. Disclaimer. Baseline characteristics of participants in the period when omicron dominated, stratified by rapid antigen test. Overall sensitivities with nasal self-sampling were 79.0% (95% confidence interval 74.7% to 82.8%) for Flowflex, 69.9% (65.1% to 74.4%) for MPBio, and 70.2% (65.6% to 74.5%) for Clinitest. WvdB, SDP, VFZ, LS, and MK were responsible for laboratory analyses and data processing. The relationship between infectious viruses, viral proteins, and RNA may differ between patient specimens and virus isolates in culture. The .gov means its official. How reliable are covid-19 lateral flow tests for detecting omicron? Professors said while omicron might currently evade one test, that same test may work to detect a new variant in the future. Prices. Study: Abbotts Rapid Test Works on Omicron, Boxes of BinaxNow home COVID-19 tests made by Abbott are shown for sale at a store, Nov. 15, 2021, in Lakewood, Wash.(Ted S. Warren/AP). Detection of SARS-CoV-2 infection in the general population by three prevailing rapid antigen tests: cross-sectional diagnostic accuracy study. We thank the participants and study staff at the participating public health service test sites, participating laboratories, University Medical Center Utrecht, and RIVM for their contributions to the study. Sensitivities decreased from 87.0% to 80.9% (P=0.16 by 2 test), 80.0% to 73.0% (P=0.60), and 83.1% to 70.3% (P=0.03), respectively, when transitioning from omicron accounting for 29% of infections to >95% of infections. Overall sensitivities with combined oropharyngeal and nasal self-sampling were 83.0% (78.8% to 86.7%) for MPBio and 77.3% (72.9% to 81.2%) for Clinitest. HHS Vulnerability Disclosure, Help Provenance and peer review: Not commissioned; externally peer reviewed. The manuscripts guarantor (KGMM) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as originally planned (and, if relevant, registered) have been explained. Ag-RDT buffer with no virus was used as a negative control. Potentially, the proportion of SARS-CoV-2 infections attributed to the omicron variant may have been higher during the combined oropharyngeal and nasal self-sampling period. RT-PCR=reverse transcription polymerase chain reaction, Flow of participants who used the Clinitest (Siemens-Healthineers) rapid antigen test with nasal or combined oropharyngeal and nasal self-sampling, Roosendaal, the Netherlands during omicron period. PLoS Med 2021;18:e1003735. Class 2 Device Recall FLOWFLEX SARSCOV2 Antigen Rapid Test. Higher sensitivities were observed after applying the viral load cut-off, but all stratification trends remained similar, except differences in sensitivity for previous SARS-CoV-2 infection status no longer appeared statistically significant for Flowflex (see supplementary figure S2). Why are more workers returning to the office in Asia and Europe than the U.S.? Since individuals in these two subgroups are not equally distributed across age and sex groups, the diagnostic performance in age and sex subgroups may be affected as well. Nina Cosdon. 2023 Mar;29(3):391.e1-391.e7. Objective To assess the performance of rapid antigen tests with unsupervised nasal and combined oropharyngeal and nasal self-sampling during the omicron period. Overall sensitivities were 79.0% (95% confidence interval 74.7% to 82.8%) for Flowflex, 69.9% (65.1% to 74.4%) for MPBio, and 70.2% (65.6% to 74.5%) for Clinitest (table 2, fig 4, fig 5, and fig 6). Epidemiologische situatie van SARS-CoV-2 in Nederland [Dutch] 2021 [updated 28 September 2021]. The test is available in 1-Pack, 2-Pack and 5-Pack. Federal government websites often end in .gov or .mil. A positive self-test result justifies prompt self-isolation without the need for confirmatory testing. For testing the diagnostic accuracy of the SCoV-2 Ag Detect Rapid Test, they collected two anterior nasopharyngeal swab samples from 802 SARS-CoV-2-infected participants reporting onset of . Individuals were eligible if aged 16 years or older and willing and able to sign a digital informed consent form in Dutch. It found four cases in which individuals transmitted the virus to others while still testing negative on rapid tests. Under these conditions, at-home tests are as effective at detecting omicron as with other variants, Sandra Adams, a professor of biology and virologist at Montclair State University, toldNew Jersey Advance Media. Real-life performance of a COVID-19 rapid antigen detection test targeting the SARS-CoV-2 nucleoprotein for diagnosis of COVID-19 due to the Omicron variant. Since the beginning of the COVID-19 pandemic, the Food and Drug Administration has authorized dozens of coronavirus tests for use in labs, doctors offices and even in homes. When the pandemic began, at-home tests were considered to be about 70% to 80% accurate. And will it take Utah for a wild ride?. News-Medical. Azeem Majid, a professor of primary care and public health at Imperial College London, notes that the test is not designed to estimate how infectious you may be. sharing sensitive information, make sure youre on a federal The mostcommon omicron-related symptomsare: Copyright 2023 Deseret News Publishing Company. Status validatie SARS-CoV-2 antigeen sneltesten, 10 Mar 2021 [Dutch]. These reinfections are most likely to have been in those who were previously infected with an earlier variant, such as Delta or Alpha. 2021 Mar 24;3(3):CD013705. We chose weekly intervals because the extent of omicrons contribution to infection in the Netherlands was assessed weekly in the national pathogen surveillance.16. When the pandemic began, at-home tests were considered to be about 70% to 80% accurate. Yet recent studies raise questions about the tests'. However, the tests had a limited ability to detect asymptomatic Omicron infections. See this image and copyright information in PMC. Accuracy and usability of saliva and nasal rapid antigen self-testing for detection of SARS-CoV-2 infection in the general population: a head-to-head comparison. Only the MPBio test with combined oropharyngeal and nasal self-sampling met the World Health Organizations standards for rapid antigen tests (80% sensitivity and 97% specificity among individuals with symptoms).19, Our pre-omicron studies, and when less than 5% of participants were confirmatory testers, found sensitivities of 72% to 83% for three different rapid antigen tests when performed by trained professionals, and 78.5% for the Roche/SD Biosensor rapid antigen test with unsupervised nasal self-sampling.72021 The sensitivities we found in the first week of the current study, when delta was still highly dominant, were similar (Flowflex 87%, MPBio 80%, and Clinitest 83%), although the percentage of confirmatory testers was much higher (21% to 24%) than in the previous studies. Positive predictive values were high throughout our study, and people with covid-19 symptoms can therefore rely on a positive rapid antigen test result irrespective of SARS-CoV-2 variant dominance or method of self-sampling. Unauthorized use of these marks is strictly prohibited. FlowFlex COVID-19 Antigen Home Test: for $9 @ Walgreens As one of the most affordable at-home Covid-19 tests, the FlowFlex is hard to find in stock online. We did not evaluate the Flowflex test for combined oropharyngeal and nasal self-sampling because the swab provided in the test kits was deemed not suitable for oropharyngeal self-sampling. The funder had no role in the design; collection, analysis, and interpretation of data; writing; and decision to submit the paper for publication. FOIA BMC Med 2022;20:97. ES performed the statistical analysis and verified the underlying data in close collaboration with RPV and KGMM. Travelers these days have plenty of COVID-19 testing options, but getting a test for travel now is more important than ever.Between the United States shortening the testing window to fly into the country from abroad to documented testing shortages to the holidays fast approaching, having more options is always a good thing.. None of them received any (financial) compensation for their contributions. Status validatie SARS-CoV-2 antigeen sneltesten, 10 Mar 2021 [Dutch]. Please use one of the following formats to cite this article in your essay, paper or report: Chaturvedi, Saurabh. This guide tells you how to: prepare the test take a swab sample from. This means you should continue to be careful, but it isnt cause for excessive concern. Fourthly, the viral load cut-off that we used was the cut-off above which 95% of people with a positive RT-PCR test result had a positive virus culture in our similar previous study.2 Those experiments were done when the alpha variant was dominant, and participants were mostly unvaccinated. But the dawn of omicron has changed the efficacy of these tests. Some home tests. Vertical line indicates sensitivity of the rapid antigen test in the overall study population, Sensitivities with 95% confidence intervals for the MPBio (MP Biomedicals) rapid antigen test using reverse transcription polymerase chain reaction (RT-PCR) as reference test, stratified according to covid-19 vaccination status, previous infection status, sex, and age, with nasal or combined oropharyngeal and nasal self-sampling. Participants were asked to complete the study procedures at home as soon as possible, and within three hours of their test site visit. All participants signed an informed consent form before any study procedure. 2021. Variables like how the test is administered can also contribute to the accuracy of the . The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. In comparison with B.1.610, the delta variant, like the alpha, beta, and gamma variants, presented higher sensitivity. Sensitivities of all three rapid antigen tests were highest during the first week (fig 7) when omicron accounted for 28.6% of infections: 87.0% (79.7% to 92.4%) for Flowflex, 80.0% (51.9% to 95.7%) for MPBio, and 83.1% (72.9% to 90.7%) for Clinitest. Rapid, point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. Sensitivities decreased from 87.0% to 80.9% (P=0.16 by 2 test), 80.0% to 73.0% (P=0.60), and 83.1% to 70.3% (P=0.03), respectively, when transitioning from omicron accounting for 29% of infections to >95% of infections. As we observed a decline in diagnostic accuracy with increasing dominance of the omicron variant in the nasal self-sampling period, the higher proportion of infections attributed to the omicron variant in the combined oropharyngeal and nasal self-sampling period may have led to an underestimation of the true difference in diagnostic accuracy between both sampling methods. The study protocol is available upon request by contacting Karel Moons at k.g.m.moons@umcutrecht.nl. Secondly, we did not determine the virus lineage in individual samples but relied on the national pathogen surveillance data to estimate the weekly prevalence of the omicron variant.16 This surveillance system includes about 2000 random samples from positive samples across the country on a weekly basis. A recent small study found that at-home antigen coronavirus tests could miss omicron cases for several days while a person is infected. Matthews suggests getting a PCR test, and if that is also positive you could seek additional medical advice, as, although unlikely, in a very small number of cases it may mean you have an underlying medical condition. Among people who tested positive for the virus on a P.C.R. Euro Surveill 2021;26:26. Stay informed daily on the latest news and advice on COVID-19 from the editors at U.S. News & World Report. The con is that they may not be as accurate very early. Dinnes J, Sharma P, Berhane S, van Wyk SS, Nyaaba N, Domen J, Taylor M, Cunningham J, Davenport C, Dittrich S, Emperador D, Hooft L, Leeflang MM, McInnes MD, Spijker R, Verbakel JY, Takwoingi Y, Taylor-Phillips S, Van den Bruel A, Deeks JJ; Cochrane COVID-19 Diagnostic Test Accuracy Group. The pro is that they give fast results in about 15 minutes, allowing you to make quick changes in behavior if you get a positive result. Matthews says that any reinfection will probably be a mild cold as you will have built up a bigger and better army of memory T and B cells, as long as you are otherwise healthy. The US Food and Drug Administration has granted an Emergency Use Authorization to an over-the-counter (OTC) COVID-19 test that agency officials say will double at-home testing capacity. 10.2807/1560-7917.ES.2021.26.44.2100441 Sensitivities were substantially higher in confirmatory testers (93.6%, 83.6%, and 85.7%, respectively) than in those who tested for other reasons (52.4%, 51.5%, and 49.5%, respectively). In our diagnostic accuracy study conducted during the emergence of omicron, we compared the performances of rapid antigen tests with nasal self-sampling versus combined oropharyngeal and nasal self-sampling. However, we believe that this estimate is still more meaningful than using arbitrary cycle threshold value cut-offs of 25 or 30, as is often done.2324 Fifthly, we did not collect detailed information on the exact timing of RT-PCR sampling and rapid antigen testing. -, Venekamp RP, Veldhuijzen IK, Moons KGM, et al. Initial studies comparing omicron with delta found similar sensitivities for molecular tests,8 mixed analytical performance of lateral flow devices,910 and similar real world sensitivities for rapid antigen tests with sampling and testing by trained professionals.1112 Additionally, anecdotal concerns were raised about the performance of such tests when applying only nasal sampling because omicron viral particles seem to be more prevalent in the throat than nose. Chaturvedi, Saurabh. The research comes as concerns have been raised in recent weeks over the accuracy of the rapid tests. Volk's advice is to wait at least five days after exposure to do a rapid test. Manufacturers of MPBio and Clinitest may consider extending their instructions for use to include combined oropharyngeal and nasal self-sampling, and other manufacturers of rapid antigen tests should consider evaluating this as well. Conclusions Sensitivities of three rapid antigen tests with nasal self-sampling decreased during the emergence of omicron but was only statistically significant for Clinitest. Centrum Infectieziektebestrijding RIVM. After carrying out tests, the UK Health Security Agency said LFTs have a comparable sensitivity for Omicron as for other Covid variants such as Delta. The Omicron BA.5 variantthe strain of COVID-19 that's currently dominating in the United Statesis good at evading immunity from both vaccines and previous COVID infection. This ensures excellent accuracy and quick and simple outcomes. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Idaho lawmaker wants to criminalize the most-used COVID-19 vaccines, What is Orthrus? RIVM Centrum Infectieziektebestrijding. However, David Matthews, a professor of virology at the University of Bristol, says that a thicker line could mean in theory at least there is more N protein. Home COVID-19 tests are hard to find, but while they do detect omicron they can miss an infection if you test to early, Doctors say find a PCR test if you think the results are wrong. Image Credit: Roman Zaeits / Shutterstock.com. The Flowflex COVID-19 Antigen Home Test, which the FDA authorized for emergency use on Oct. 4, gave a correct positive result 93% of the time and a correct negative result 100% of the time in a . But the dawn of omicron has changed the efficacy of these tests. Testing is always by RT-PCR, free of charge, but only available for government approved test indications. BD Veritor (Becton Dickinson) Okay (marginally acceptable) 51.8. Vertical line indicates sensitivity of the rapid antigen test in the overall study population, Sensitivities with 95% confidence intervals for the Clinitest (Siemens-Healthineers) rapid antigen test using reverse transcription polymerase chain reaction (RT-PCR) as reference test, stratified according to covid-19 vaccination status, previous infection status, sex, and age, with nasal or combined oropharyngeal and nasal self-sampling. Overall sensitivities with nasal self-sampling were 79.0% (95% confidence interval 74.7% to 82.8%) for Flowflex, 69.9% (65.1% to 74.4%) for MPBio, and 70.2% (65.6% to 74.5%) for Clinitest. Testing for adults and children ages 2+ years, with or . We believe all of them detect omicron, she said of the at-home rapid tests. The new guidance applies to everyone who has tested positive, regardless of vaccination status. Sensitivity. This large diagnostic accuracy evaluation of three commercially available SARS-CoV-2 rapid antigen tests (Flowflex, MPBio, and Clinitest) with unsupervised nasal self-sampling by individuals with symptoms showed a decline in overall sensitivities with the emergence of omicron. There's also concern that rapid at-home antigen tests are less effective at detecting the variant, too. Manufacturers of MPBio and Clinitest may consider extending their instructions for use to include combined oropharyngeal and nasal self-sampling, and other manufacturers of rapid antigen tests should consider evaluating this as well. This was the viral load cut-off above which 95% of people with a positive RT-PCR test result had a positive virus culture result based on previous work.2 Furthermore, considering the large influence of confirmatory testers in our study populations, all analyses were repeated stratified by confirmatory testing (yes or no). Participants: Three public health service covid-19 test sites in the Netherlands, 21 December 2021 to 10 February 2022. Whether or not symptoms exist, the Flowflex antigen test is all that is required to determine your family's COVID-19 condition.