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. Issue 11 (November 2021)

• Record Type: Journal Article
• Authors: Nomoto, Hidetoshi; Yamamoto, Kei; Yamada, Gen; Suzuki, Michiyo; Kinoshita, Noriko; Takasaki, Jin; Moriya, Ataru; Maeda, Kenji; Kimura, Motoi; Ohmagari, Norio
• Is Part Of: Journal of infection and chemotherapy. Volume 27:Issue 11(2021)
• Page Start: 1669
• Page End: 1673
• Publication Date: 2021-11
• Subjects: Lumipulse -- Quantitative antigen test -- Infectivity assessment -- Nasopharyngeal swab -- COVID-19 -- SARS-CoV-2; Ag antigen -- CI confidence interval -- CLEIA chemiluminescence enzyme immunoassay -- COVID-19 COVID-19 -- LOESS locally estimated scatterplot smoothing -- NCGM National Center for Global Health and Medicine -- NIID National Institute of Infectious Diseases -- PCR polymerase chain reaction -- QAT quantitative antigen test -- RATs rapid antigen test -- ROC receiver operating characteristic curve -- RT-qPCR reverse-transcription quantitative polymerase chain reaction -- SARS-CoV-2 severe acute respiratory syndrome coronavirus 2 -- VTM viral transport medium; Chemotherapy -- Periodicals; Infection -- Periodicals; Communicable diseases -- Chemotherapy -- Periodicals; 615.5805
• DOI: 10.1016/j.jiac.2021.08.015
• Languages: English
• ISSNs: 1341-321X

Abstract

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.