Analytical and clinical evaluation of a heat shock SARS-CoV-2 detection method without RNA extraction for N and E genes RT-qPCR. (August 2021)

• Record Type: Journal Article
• Authors: Bruno, Alfredo; de Mora, Domenica; Freire-Paspuel, Byron; Rodriguez, Angel S.; Paredes-Espinosa, Maria Belen; Olmedo, Maritza; Sanchez, Martha; Romero, Jennifer; Paez, Michelle; Gonzalez, Manuel; Orlando, Alberto; Garcia-Bereguiain, Miguel Angel
• Is Part Of: International journal of infectious diseases. Volume 109(2021)
• Page Start: 315
• Page End: 320
• Publication Date: 2021-08
• Subjects: SARS-CoV-2 -- RT-qPCR -- RNA extraction free -- Heat shock -- COVID-19; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2021.06.038
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: Heat shock based SARS-CoV-2 RT-PCR diagnosis has a sensitivity up to 89.4%. For 100.000 copies/mL LoD, the sensitivity is as high as 98.6%. Heat shock based SARS-CoV-2 RT-PCR is a reliable tool for low resources settings. Abstract: Background: The COVID-19 pandemic has caused significant supply shortages worldwide for SARS-CoV-2 molecular diagnosis, like RNA extraction kits. Objective: 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. Results: 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) of 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. Conclusions: 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 at the time of testing. This affordable protocol can help 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.