1. Time-course evaluation of the quantitative antigen test for severe acute respiratory syndrome coronavirus 2: The potential contribution to alleviating isolation of COVID-19 patients
- Author
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Kenji Maeda, Gen Yamada, Noriko Kinoshita, Michiyo Suzuki, Kei Yamamoto, Motoi Kimura, Ataru Moriya, Hidetoshi Nomoto, Jin Takasaki, and Norio Ohmagari
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Lumipulse ,LOESS, locally estimated scatterplot smoothing ,Ag, antigen ,CLEIA, chemiluminescence enzyme immunoassay ,COVID-19, COVID-19 ,medicine.disease_cause ,SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 ,Gastroenterology ,PCR, polymerase chain reaction ,Internal medicine ,medicine ,Cutoff ,Pharmacology (medical) ,RT-qPCR, reverse-transcription quantitative polymerase chain reaction ,Stage (cooking) ,NIID, National Institute of Infectious Diseases ,Mass screening ,Coronavirus ,Receiver operating characteristic ,SARS-CoV-2 ,business.industry ,COVID-19 ,Infectivity assessment ,Retrospective cohort study ,Note ,Quantitative antigen test ,VTM, viral transport medium ,CI, confidence interval ,NCGM, National Center for Global Health and Medicine ,RATs, rapid antigen test ,Infectious Diseases ,Real-time polymerase chain reaction ,QAT, quantitative antigen test ,Nasopharyngeal swab ,ROC, receiver operating characteristic curve ,business - Abstract
Introduction The automated quantitative antigen test (QAT), which detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is suitable for mass screening. However, its diagnostic capability differentiated by time from onset and potential contribution to infectivity assessment have not been fully investigated. Methods A retrospective, observational study using nasopharyngeal swab specimens from coronavirus disease (COVID-19) inpatients was conducted using LumipulseⓇ SARS-CoV-2 antigen test. Diagnostic accuracy was examined for the early (up to 10 days after onset) and late (over 10 days after onset) stages. Time-course QAT changes and reverse‐transcription quantitative polymerase chain reaction tests results were displayed as locally estimated scatterplot smoothing curve, and receiver operating characteristic curve (ROC) analysis was used to determine the appropriate cutoff value for differentiating the early and late stages. Results We obtained 100 specimens from 68 COVID-19 patients, including 51 early-stage and 49 late-stage specimens. QAT sensitivity and specificity were 0.82 (0.72–0.90) and 0.95 (0.75–0.99) for all periods, 0.93 (0.82–0.98) and 1.00 (0.39–1.00) for the early stage, and 0.66 (0.48–0.82) and 0.93 (0.69–0.99) for the late stage, respectively. The ROC analysis indicated an ideal cutoff value of 6.93 pg/mL for distinguishing early-from late-stage specimens. The sensitivity, specificity, positive predictive value, and negative predictive value for predicting the late stage were 0.76 (0.61–0.87), 0.76 (0.63–0.87), 0.76 (0.61–0.87), and 0.76 (0.63–0.87). Conclusions QAT has favorable diagnostic accuracy in the early COVID-19 stages. In addition, an appropriate cutoff point can potentially facilitate rapid identification of noncontagious patients.
- Published
- 2021
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