Negar Sadeghi , Neda Shirazi , Moein Dehbashi , Bahareh Maleki , William C. Cho , Zohreh Hojati
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引用次数: 0
Abstract
Introduction
In response to the rapid spread of the SARS-CoV-2 virus, we developed a rapid molecular approach to diagnose COVID-19 without the need for RNA extraction.
Methods
The study utilized two molecular methods, RT-qPCR and colorimetric RT-LAMP, to diagnose the RdRp and ORF8 genes, respectively, in oro-nasopharyngeal swabs. Due to the high sequence diversity of ORF8 in SARS-CoV and SARS-CoV-2, it has been identified as a suitable target for virus detection. The RT-LAMP method was also carried out directly on heat-treated swab samples. The strip tests were made using gold nanoparticles and combined with the RT-LAMP for further analysis.
Results
The results showed that the isothermal amplification method had a sensitivity of 95 % (95 % C.I.: 86.08 %–98.96 %) and a specificity of 75 % (95 % C.I.: 19.41 %–99.37 %). The RT-LAMP-LFA method was able to distinguish positive and negative samples with 100 % sensitivity (95 % C.I.: 91.96–100) and 77.27 % specificity (95 % C.I.: 54.63–92.18). This method only required heating swab samples for 10 min at 65 °C before the RT-LAMP reaction.
Conclusion
By utilizing the RT-LAMP in combination with the LFA, it is possible to diagnose SARS-CoV-2 rapidly without the need for RNA extraction. The entire process from sample collection to test interpretation takes only 75–90 min, and the results can be interpreted by untrained individuals with the naked eye. By employing the ORF8 gene as a diagnostic target and eliminating the need for RNA extraction, the direct RT-LAMP-LFA method achieves a significant breakthrough that was not previously reported.
期刊介绍:
Practical Laboratory Medicine is a high-quality, peer-reviewed, international open-access journal publishing original research, new methods and critical evaluations, case reports and short papers in the fields of clinical chemistry and laboratory medicine. The objective of the journal is to provide practical information of immediate relevance to workers in clinical laboratories. The primary scope of the journal covers clinical chemistry, hematology, molecular biology and genetics relevant to laboratory medicine, microbiology, immunology, therapeutic drug monitoring and toxicology, laboratory management and informatics. We welcome papers which describe critical evaluations of biomarkers and their role in the diagnosis and treatment of clinically significant disease, validation of commercial and in-house IVD methods, method comparisons, interference reports, the development of new reagents and reference materials, reference range studies and regulatory compliance reports. Manuscripts describing the development of new methods applicable to laboratory medicine (including point-of-care testing) are particularly encouraged, even if preliminary or small scale.