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.
Keywords: COVID-19; Infectivity assessment; Lumipulse; Nasopharyngeal swab; Quantitative antigen test; SARS-CoV-2.
【저자키워드】 COVID-19, SARS-CoV-2, Nasopharyngeal swab, Lumipulse, infectivity assessment, Quantitative antigen test, 【초록키워드】 coronavirus disease, SARS-CoV-2, coronavirus, diagnostic, severe acute respiratory syndrome Coronavirus, observational study, Predictive value, Antigen, Nasopharyngeal swab, polymerase chain reaction, sensitivity, specificity, Infectivity, Diagnostic accuracy, Positive predictive value, Mass screening, ROC, Accuracy, Sensitivity and specificity, automated, SARS-CoV-2 antigen, characteristic, change, Quantitative, specimens, early stage, patients, COVID-19 patients, ROC analysis, retrospective, Analysis, Nasopharyngeal swab specimens, Negative predictive value, receiver operating characteristic, Chain Reaction, Inpatients, Inpatient, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, stages, specimen, late stage, cutoff value, cutoff point, nasopharyngeal swab specimen, polymerase chain, was used, detect, examined, indicated, addition, investigated, conducted, facilitate, determine, scatterplot, 【제목키워드】 coronavirus, Antigen, Isolation, Quantitative, COVID-19 patient, acute respiratory syndrome,