Evaluation of RT-LAMP and Dry Swab RNA Extraction Free Method for Detection of SARS-CoV-2 Infection
DOI:
https://doi.org/10.21467/preprints.436Abstract
Background: A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in December 2019 in Wuhan, China. Due to high infectious rate of SARS-CoV-2, detection of positive patients is one of the key points to controlling the outbreak. The gold standard for diagnosis of SARS-CoV-2 remains RT-PCR. In the current pandemic, a more rapid and high throughput method is in growing concern.
Objectives: To evaluate the RT-LAMP and dry swab RNA extraction free method in diagnosing SARS-CoV-2 infection, using reverse transcription polymerase chain reaction (RT-PCR) as gold standard.
Methods: A laboratory based cross-sectional descriptive study was carried out from September 2022 to October 2022 at molecular laboratory of No (1) Defence Services General Hospital. Ninety-four nasopharyngeal swabs were collected and tested for the presence of SARS-CoV-2 infection by RT-PCR (gold standard), RT-LAMP and dry swab method.
Result: In this study, 68 (72.3%) out of 94 patients were positive for SARS CoV-2 infection by RT-PCR. The overall sensitivity, specificity, positive predictive value and negative predictive value of RT-LAMP was 76.5%, 100%, 100% and 62%. The overall sensitivity, specificity, positive predictive value and negative predictive value of dry swab method was 66%, 100%, 100% and 53%. Hundred percent sensitivity was occurred in RT-LAMP and Dry swab method with Ct<20. In Ct 20-30, sensitivity of RT-LAMP and Dry swab method was 94.8% and 89.7%.
Conclusions: RT-PCR method exist as a gold standard for diagnosis of SARS CoV-2, it required molecular laboratory; RT-PCR machine and reagents; they are expensive; trained technician; and it takes several hours to get the results. Although sensitivity and specificity of RT-LAMP and dry swab methods are inferior to RT-PCR, they can be performed easily in the short period of time (less than 2 hours). Therefore, faster, cheaper and easier alternative molecular diagnostic methods should be considered for diagnosis of SARs CoV-2 infection.
Keywords:
SARS-CoV-2, RT-PCR, RT-LAMPDownloads
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