Analytical and clinical evaluation of a heat shock SARS-CoV-2 detection method without RNA extraction for N and E genes RT-qPCR

Abstract

\n Background\n : The COVID-19 pandemic has caused significant supply shortages worldwide for SARS-CoV-2 molecular diagnosis, like RNA extraction kits.\n \n Objective\n : The aim of our study was to evaluate the clinical performance and analytical sensitivity of a simple SARS-CoV-2 diagnosis protocol based on heat shock without RNA extraction using both CDC (N gene) and Charite (E gene) RT-qPCR protocols.\n \n Results\n : 1,036 nasopharyngeal samples, 543 of them SARS-CoV-2 positive, were analyzed. The heat shock method correctly identified 68,8% (232/337) and 89.4% (202/226) SARS-CoV-2 positive samples for N gene and E gene, respectively. Analytical sensitivity was assessed for heat shock method using the CDC RT-qPCR protocol, obtaining sensitivity values of 98,6%, 93,3% and 84,8% for limit of detection of 100.000, 50.000 and 20.000 viral RNA copies/mL of sample.\n \n Conclusions\n : Our findings show that a simple heat shock SARS-CoV-2 RT-qPCR diagnosis method without RNA extraction is a reliable alternative for potentially infectious SARS-CoV-2 positive patients. This affordable protocol can help to overcome the cost and supply shortages for SARS-CoV-2 diagnosis, especially in developing countries. In Ecuador, it has been used already by laboratories in the public health system for more than 100.000 specimens.\n