Development and performance evaluation of a low-cost in-house rRT-PCR assay in Ecuador for the detection of SARS-CoV-2

Salinas, M.; Aguirre, D.; De la Torre, D.; Perez-Galarza, J.; Pibaque, R.; Beltran, P.; Veloz, T.; Baldeon, L.

Antecedents: Ecuador has had the greatest fatality rate from Coronavirus (COVID-19) in South America during the SARS-CoV-2 pandemic. To control the pandemic, it is necessary to test as much population as possible to prevent the spread of the SARS-CoV-2 infection. For the Ecuadorian population, accessing a PCR test is challenging, since commercial screening kits tend to be expensive. Objective: the objective of this study was to develop an in-house duplex rRT-PCR protocol for the detection of SARS-CoV-2 that contributes to the screening while keeping quality and low testing costs. Results: An in-house duplex rRT-PCR protocol based on the viral envelope (E) gene target of SARS-CoV-2 and a human ribonuclease P gene (RP) as an internal control is reported. The protocol was optimized to obtain primers E with an efficiency of up to 94.45% and detection of 100% of SARS-CoV-2 up to 15 copies per uL. The clinical performance was determined by a sensibility of 93.8% and specificity of 98.3%. Conclusion: we developed, standardized, and validated a low-cost, sensitive in-house duplex rRT-PCR assay that may be utilized in low-income countries.