ABSTRACT
The promising diagnostic performance of rapid antigen tests (RATs) using non-invasive anterior nasal (AN) swab specimens to diagnose COVID-19 has been reported. A large number of RATs are commercially available; however, the careful assessment of RATs is essential prior to their implementation in clinical practice. We evaluated the clinical performance of the GLINE-2019-nCoV Ag Kit as a RAT using AN swabs in a prospective, blinded study. Adult patients who visited outpatient departments and received SARS-CoV-2 tests between August 16 and September 8, 2022, were eligible for this study. Patients who were aged under 18 years and patients without appropriate specimens were excluded. Two sets of AN and nasopharyngeal (NP) swabs were collected from all patients. Each set of specimens was tested by the RAT and quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Of the 138 recruited patients, 84 were positive and 54 were negative by RT-qPCR using NP swabs. The positive agreement rate between RT-qPCR using NP swabs and RAT using AN swabs was 78.6% (95% confidence interval [CI], 68.3%-86.8%), the negative agreement rate was 98.1% (95% CI, 90.1%-99.9%), and the overall agreement rate was 86.2% (95% CI, 79.3%-91.5%), with a κ coefficient of 0.73. The positive agreement rate in the early phase (≤3 days from symptom onset) was >80%, but this fell to 50% in the late phase (≥4 days). This study demonstrates that the GLINE-2019-nCoV Ag Kit using AN swabs has good clinical performance and might be a reliable alternative method for diagnosing COVID-19.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , Nasal Cavity , Prospective Studies , Immunologic Tests , Nasopharynx , Sensitivity and SpecificityABSTRACT
BACKGROUND: In the context of the coronavirus disease 2019 (COVID-19) pandemic, a rapid and reliable point-of-care test is an essential tool for controlling the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In particular, an immunochromatography test (ICT) that uses saliva specimens for rapid antigen detection not only reduces the risk of secondary infections but also reduces the burden on medical personnel. METHODS: The newly developed salivary antigen test kit "Inspecter Kowa® SARS-CoV-2" is an ICT to which saliva specimens can be directly applied. We evaluated its usefulness in comparison with reverse transcription quantitative PCR (RT-qPCR) and the Espline® SARS-CoV-2 Kit for the detection of SARS-CoV-2 using nasopharyngeal swab specimens. In this study, 140 patients with suspected symptomatic COVID-19 who visited our hospital were enrolled, and nasopharyngeal swab and saliva specimens were collected after they consented to participate in the study. RESULTS: Inspector Kowa SARS-CoV-2 was positive in 45 of 61 (73.8%) saliva that were positive by RT-qPCR and the Espline® SARS-CoV-2 Kit was also positive in 56 of 60 (93.3%) Np swabs that were positive by RT-qPCR. Good antigen detection was achieved by ICT with saliva and nasopharyngeal swab specimens when viral load was ≥105 copies/mL, whereas detection sensitivity was low when viral load was <105 copies/mL, especially in saliva specimens. CONCLUSION: This ICT for the detection of SARS-CoV-2 salivary antigen is an attractive tool that does not require specialized equipment and allows patients to perform the entire process from sample collection to self-diagnose and to reduce the burden on medical care during a pandemic.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19 Testing , Saliva , Clinical Laboratory Techniques/methods , Specimen Handling/methods , NasopharynxABSTRACT
A high-throughput, fully automated antigen detection test for SARS-CoV-2 is a viable alternative to reverse-transcription polymerase chain reaction (RT-qPCR) for mass screening during outbreaks. In this study, we compared RT-qPCR for viral load and the VITROS® SARS-CoV-2 Antigen Test with reference to the results of the LUMIPULSE® SARS-CoV-2 Ag Test. Of 128 nasopharyngeal swab specimens taken from patients suspected of being infected with SARS-CoV-2, 49 were positive and 79 were negative according to RT-qPCR. Consistent dose-dependent detection with VITROS® assay was successfully achieved when using nasopharyngeal swab specimens with Ct values of 32.0 or lesser, whereas the CLEIA-based LUMIPULSE® assay was able to detect lower viral loads compared with the VITROS® assay. Our results show that the performance of the VITROS® assay was satisfactory for the diagnosis of contagious COVID-19 patients in the clinical setting. Highlights The performance of the VITROS® SARS-CoV-2 Antigen Test was sufficient for the diagnosis of contagious COVID-19. This test showed high sensitivity and specificity in the detection of SARS-CoV-2 in samples with a Ct value of 32 or less.