Technical Note: RNA Extraction Alternative Method for SARS-CoV-2 Molecular Diagnosis

Abstract

The devastating COVID-19 outbreak posed serious challenges for the diagnostics laboratories, facing global shortage of reagents and equipment. This study aimed at evaluating an additional RNA extraction method respect to those already recommended by WHO and CDC. A new protocol for RNA extraction from nasopharyngeal swab was set up, adapting a Qiagen kit, and validated on a set of 96 clinical samples. The analysis showed a sensitivity of 94% and a specificity of 97%, but considering samples with Ct<36.5, the sensitivity and the specificity increased to 100%. The adapted method was also able to detect samples with very low viral load (Ct>38), indicating that the two approaches can be considered equivalent for the SARS-CoV-2 diagnostics. This extraction method can help in increasing the throughput for SARS-CoV-2 molecular test, even in a low automation setting.

Keywords: COVID-19; RNA extraction; RT-PCR; SARS-CoV-2; nasopharyngeal swab.