{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T20:10:28Z","timestamp":1778703028899,"version":"3.51.4"},"reference-count":20,"publisher":"Public Library of Science (PLoS)","issue":"4","license":[{"start":{"date-parts":[[2021,4,8]],"date-time":"2021-04-08T00:00:00Z","timestamp":1617840000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"crossref","award":["2020R1A5A1018052"],"award-info":[{"award-number":["2020R1A5A1018052"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>We evaluated the diagnostic accuracy of two newly developed, point-of-care, rapid antigen tests (RATs) for detecting SARS-CoV-2, the AFIAS COVID-19 Ag and the ichroma<jats:sup>TM<\/jats:sup>COVID-19 Ag, and investigated antigen kinetics. A total of 200 serially collected nasopharyngeal (NP) specimens from 38 COVID-19 patients and 122 specimens from negative controls were analyzed. Diagnostic sensitivity and specificity were assessed in comparison to molecular test results and subdivided according to targeted genes (<jats:italic>E<\/jats:italic>,<jats:italic>RdRP<\/jats:italic>, and<jats:bold><jats:italic>N<\/jats:italic><\/jats:bold>) and days post-symptom onset (PSO). For the kinetics evaluation, cut-off-indices from serial NP specimens were used according to the number of days PSO. Both RATs showed sensitivity of 91.3\u2012100% for specimens with cycle threshold (Ct) &lt; 25. The specificity of AFIAS was 98.7\u201298.9% and that of ichroma<jats:sup>TM<\/jats:sup>was 100.0%. The kappa values of AFIAS and ichroma<jats:sup>TM<\/jats:sup>for the molecular testing of specimens with Ct &lt; 25 (<jats:italic>RdRP<\/jats:italic>) were 0.97 and 1.00, respectively. The sensitivity of AFIAS and ichroma<jats:sup>TM<\/jats:sup>for all genes was lower for specimens collected at 8\u201214 PSO than for those collected before 7-days PSO. The kinetics profiles showed that antigen levels gradually decreased from \u2264 7-days PSO to &gt; 22-days PSO. Both RATs showed excellent specificity and acceptable sensitivity for NP specimens with higher viral loads and for specimens collected within 7-days PSO. Hence, they have the potential to become useful tools for the early detection of SARS-CoV-2. However, because of concerns about false negativity, RATs should be used in conjunction with molecular tests.<\/jats:p>","DOI":"10.1371\/journal.pone.0249972","type":"journal-article","created":{"date-parts":[[2021,4,8]],"date-time":"2021-04-08T18:01:06Z","timestamp":1617904866000},"page":"e0249972","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":22,"title":["Evaluation of rapid SARS-CoV-2 antigen tests, AFIAS COVID-19 Ag and ichroma COVID-19 Ag, with serial nasopharyngeal specimens from COVID-19 patients"],"prefix":"10.1371","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4751-7384","authenticated-orcid":true,"given":"Oh Joo","family":"Kweon","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yong Kwan","family":"Lim","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hye Ryoun","family":"Kim","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoojeong","family":"Choi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Min-Chul","family":"Kim","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Seong-Ho","family":"Choi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jin-Won","family":"Chung","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1824-476X","authenticated-orcid":true,"given":"Mi-Kyung","family":"Lee","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2021,4,8]]},"reference":[{"issue":"3","key":"pone.0249972.ref001","volume":"25","author":"VM Corman","year":"2020","journal-title":"Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. 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