STUDY AND PRODUCE RNA-POSITIVE STANDARD REFERENCE SAMPLES OF SARS-COV-2 VIRUS FOR QUALITY CONTROL OF COVID-19 DIAGNOSTIC KIT

Abstract

Background/Purpose: This study aims to establish the procedure for the production of RNA-positive reference samples of the SARS-CoV-2 virus from inactivated cultures, and to evaluate the stability of RNA samples under different storage conditions.

Methods: Methods of describing experiments in the laboratory.

Results: The study developed a procedure for the production of a SARS-CoV-2 RNA positive control based on WHO requirements for setting up a secondary RNA standard. From the culture fluid of the inactivated international strain of SARS-CoV-2, through the extraction and quantity of RNA concentration and stability assessment of samples at different concentrations, then select the lowest sample concentration that still ensures stability over real storage time. The stability assessment is conducted at 3 levels of sample concentration: 5x104cp/µl, 104cp/µl, and 2x103cp/µl and under the following storage conditions: at -70⁰C after 3 months, 6 months, and 8 months; the number of thaws; store at 25⁰C and 4⁰C for 6 weeks.

Conclusion: Developed a production process and produced 15 tubes of SARS-CoV-2 RNA positive control samples at a concentration of 2x103cp/µl with a volume of each tube of 40 µl/tube. The produced SARS-CoV-2 RNA positive controls were tested and found to be stable through 8 months of storage at -70⁰C, 10 times of thawing, and for at least 1 month at 25⁰C and 4⁰C.