ABSTRACT
The current pandemic of COVID-19 caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) has raised significant public health concerns. Rapid and accurate testing of SARS-CoV-2 is urgently needed for early detection and control of the disease spread. Here, we present an RT-LAMP coupled glass nanopore digital counting method for rapid detection of SARS-CoV-2. We validated and compared two one-pot RT-LAMP assays targeting nucleocapsid (N) and envelop (E) genes. The nucleocapsid assay was adopted due to its quick time to positive and better copy number sensitivity. For qualitative positive/negative classification of a testing sample, we used the glass nanopore to digitally count the RT-LAMP amplicons and benchmarked the event rate with a threshold. Due to its intrinsic single molecule sensitivity, nanopore sensors could capture the amplification dynamics more rapidly (quick time to positive). We validated our RT-LAMP coupled glass nanopore digital counting method for SARS-CoV-2 detection by using both spiked saliva samples and COVID-19 clinical nasopharyngeal swab samples. The results obtained showed excellent agreement with the gold standard RT-PCR assay. With its integration capability, the electronic nanopore digital counting platform has significant potential to provide a rapid, sensitive, and specific point-of-care assay for SARS-CoV-2.
Subject(s)
Biosensing Techniques , COVID-19 , Nanopores , Humans , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , RNA, Viral , SARS-CoV-2 , Sensitivity and SpecificityABSTRACT
BACKGROUND: In the absence of a safe, effective vaccine, the worldwide spread of COVID-19 (SARS-CoV-2) infection will continue. Laboratory tests with ideal precision, sensitivity, and specificity should be used in public health and clinical settings to gauge the extent of virus exposure. Toward this end, we evaluated the analytical and clinical performance of the Abbott SARS-CoV-2 IgG and the Roche Anti-SARS-CoV-2 immunoassays. METHODS: Quality control, pooled COVID-19, and non-COVID-19 patient specimens were used for the imprecision study. Two hundred and forty-six specimens from 70 patients with COVID-19 diagnosis were tested to study the sensitivity. Seventy-three non-COVID-19 control specimens were measured to study the specificity. All specimens were analyzed by both assays. RESULTS: Total analytic variability (CV) of the negative and positive controls were 5.5% and 3.6% for the Abbott assay and 4.5% and 1.9% for the Roche assay. Both assays demonstrated 100% qualitative reproducibility of negative and positive controls. The clinical specificities of the Abbott and the Roche assays were 100% (95% CI: 94%-100%) and 97% (95% CI: 90%-100%), respectively. The clinical sensitivities of the Abbott assay were 49% (95% CI: 41%-56%), 86% (95% CI: 74%-93%), and 100% (95% CI: 76%-100%) for samples collected at 0-6 days, 7-13 days, and ≥14 days after the first RT-PCR, while the sensitivities of the Roche assay were 55% (95% CI: 47%-62%), 86% (95% CI: 74%-93%), and 100% (95% CI: 76%-100%). CONCLUSIONS: This study demonstrates similar analytical and clinical performance of the Abbott and the Roche SARS-CoV-2 antibody assays, but the Roche assay may be slightly more sensitive for patients tested within 0-6 days after first positive RT-PCR of SARS-CoV-2.COVID-19 is a respiratory infectious disease caused by SARS-CoV-2. Laboratory tests with ideal precision, sensitivity, and specificity should be used in public health and clinical settings. We analyzed analytical and clinical performance of the Roche and Abbott SARS-CoV-2 antibody assays in pre-pandemic and pandemic patient populations. Additionally, we analyzed the sensitivity of both assays in patients at different stages of the disease. The 2 assays showed similar analytical and clinical performance, but the Roche assay may be slightly more sensitive for patients tested within 0-6 days after first positive RT-PCR of SARS-CoV-2. Our findings help other clinical labs select appropriate assays for SARS-CoV-2 antibody testing.