A prospective clinical evaluation of the diagnostic accuracy of the SARS-CoV-2 rapid antigen test using anterior nasal samples.

INTRODUCTION: The diagnostic accuracy of antigen testing of anterior nasal (AN) samples for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has not been evaluated in the Japanese population. This study assessed the diagnostic accuracy of the Roche SARS-CoV-2 rapid antigen test (rapid antigen test) using AN samples. METHODS: Two AN samples and one nasopharyngeal (NP) sample were collected from individuals undergoing screening for SARS-CoV-2 infection. The results of the rapid antigen test and the reverse-transcription polymerase chain reaction (RT-PCR) test using AN samples were compared to those of RT-PCR tests using NP samples. RESULTS: Samples were collected from 800 participants, 95 and 110 of whom tested positive for SARS-CoV-2 on RT-PCR tests of AN and NP samples, respectively. The overall sensitivity/specificity of the AN rapid antigen test and AN RT-PCR were 72.7%/100% and 86.4%/100%, respectively. In symptomatic cases, the sensitivities of the AN rapid antigen test and AN RT-PCR were 84.7% and 94.9%, respectively. In asymptomatic cases, the sensitivities of the AN rapid antigen test and AN RT-PCR were 58.8% and 76.5%, respectively. The sensitivity of the AN rapid antigen test was over 80% in cases with cycle threshold (Ct) values < 25; it significantly decreased with an increase in the Ct values (p < 0.001). CONCLUSION: The rapid antigen test with AN samples had a favorable sensitivity, especially in symptomatic cases or in cases with Ct values < 25. It gave no false-positive results. Compared with AN-RT PCR, the AN rapid antigen test had a modestly lower sensitivity in asymptomatic cases.

Electrochemical immunosensor for rapid and highly sensitive detection of SARS-CoV-2 antigen in the nasal sample.

A label-free electrochemical biosensing approach as an appropriate analysis technique for SARS-CoV-2 spike protein (SARS-CoV-2 S-protein) was investigated to facilitate the diagnosis of coronavirus in real samples. It is crucial to construct diagnostic features that can rapidly identify infected individuals to limit the spread of the virus and assign treatment choices. Therefore, a novel and selective method using SiO2@UiO-66 and a label-free electrochemical immunoassay for rapidly detecting spike protein. The development of innovative approaches for direct viral detection employing simplified and ideally reagent-free assays is a pressing and difficult topic. The absence of speedy and effective ways to diagnose viral diseases especially SARS-CoV-2 on demand has worsened the issue of combating the COVID-19 pandemic. The developed electrode illustrated a wide dynamic range of 100.0 fg mL-1 to 10.0 ng mL-1 with low limit detection. Therefore, the as-fabricated electrochemical SARS-CoV-2 S-protein sensor suggests an appropriate perspective in the point-of-care system, within 5.0 min, in nasal samples with satisfactory recovery.

Evaluation of sampling locations in pregnant women and newborns for the detection of colonisation with antibiotic-resistant bacteria.

Up to now, little has been known about the prevalence and clinical relevance of colonisation of asymptomatic pregnant women with methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) or extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli. In this two-centre cross-sectional study, we evaluated the performance and importance of screening at different times and different locations for colonisation in pregnant women and newborns. Between October 2013 and December 2015, four samples were collected from pregnant women, two from newborns at birth and three from 3-day-old newborns. Samples were screened on culturing media and were confirmed with molecular methods. MSSA was used as a surrogate for MRSA, as the two share most microbiologic characteristics and colonisation patterns. Of 763 pregnant women, 14.5% (111) were colonised with MSSA, 0.4% (3) with MRSA and 2.6% (20) with ESBL-producing E. coli. Of 658 newborns, 0.9% (10) were colonised with MSSA at birth and 13.1% (70) at 3 days old, 0.5% (3) were colonised with MRSA and 2.6% (17) with ESBL-producing E. coli. Nasal sampling identified 91.0% of MSSA-colonised pregnant women and 60.0% of newborns. In newborns, nasal and umbilical sampling at 3 days after birth discovered 84.0% of colonised cases. For ESBL-producing E. coli, the perianal region was positive in all colonised pregnant women and in 88.2% of colonised newborns. Combining nasal and perianal swabs is optimal when screening for antibiotic-resistant bacteria in pregnant women. Nasal, perianal and umbilical sample collection from 3-day-old newborns significantly increased the sensitivity compared to screening immediately after birth.