Stability of SARS-CoV-2 RNA in Viral Lysis Buffer Stored at Different Temperatures

Abstract

Objectives The present COVID-19 pandemic resulted in an increased need for molecular diagnostic testing. Delay in the specimen processing and suboptimal storage of suspected samples in laboratories leads to degradation of SARS-CoV-2 viral RNA. Viral lysis buffers from RNA extraction kits have the potential to stabilize RNA. Hence, this study aimed to investigate the stability of SARS-CoV-2 RNA in viral lysis buffer at different temperatures and time periods. Materials and Methods Aliquots of samples with known SARS-CoV-2 RNA were processed in viral lysis buffers simultaneously, stored separately at 2 to 8°C and 22 to 28°C for 24 hours, 48 hours and 72 hours. SARS-CoV-2 viral RNA was extracted from each aliquot and analyzed using multiplex real-time PCR. Results SARS-CoV-2 RNA in samples placed in viral lysis buffer was stable for 48 hours at both 2 to 8°C and 22 to 28°C temperatures. Slight decline in the viral RNA quantity was found on aliquots tested after 48 hours of both the temperatures. Conclusions Viral lysis buffer maintains the integrity of SARS-CoV-2 RNA for up to 48 hours even at room temperature and supports delayed diagnosis with an overwhelming sample load in testing laboratories.

Advancements in Testing Strategies for COVID-19

“…The low viral loads hinder the accurate screening of the viral genome that cause false-negative testing [ 252 , 253 , 254 , 255 ]. Stable viral lysis buffer at different temperature ranges [ 256 ], acid pH ranges [ 257 ], and RNA extraction free detection [ 248 , 251 , 257 , 258 , 259 ] are the promising strategies for viral RNA storage and stability. Furthermore, the RNA stabilization method for a long duration at room temperature can meet the limitations.…”

Evaluation of long-term stability of SARS-CoV-2 nucleic acid extracted from human nasopharyngeal samples

“…Thus, as strategy to minimize delays and optimize the workflow, some diagnostic centers are extracting the RNA from the nasopharyngeal samples and keeping them at low temperatures before testing by RT-qPCR. As a known fact, the conditions under which the RNA was handled certainly define the quality of samples ( Perumal et al, 2020 ). Furthermore, the extracted RNA from positive samples that was properly stored can be sent for screening of variants by sequencing in Reference Centers.…”