Optimizing RT-PCR detection of SARS-CoV-2 for developing countries using pool testing.

Farfan, Mauricio J; Torres, Juan P; O'Ryan, Miguel; Olivares, Mauricio; Gallardo, Pablo; Lastra, Jorge; Salas, Carolina

The global shortage of reagents and kits for nucleic acid extraction and molecular detection of SARS-CoV-2 requires new cost-effective strategies for the diagnosis of suspected COVID-19 cases, especially in countries that need to increase detection capacity. Pooled nucleic acid testing has been extensively used as a cost-effective strategy for HIV, HepB, HepC and influenza. Also, protocols dispensing of RNA extraction appears as an attractive option for detection of SARS-CoV-2. In this study, we found that pooling of 5 samples showed that CT variations were in the range of 1.0-4,5 units, with less likelihood of a false negative result. Results of the sample without nucleic acid ex-traction, was unsatisfactory, with a significant increase in CT values, and thus for risk of a false negative result. In conclusion, pooling nasopharyngeal samples with both automated and manual extraction proved reliable, and thus a potential efficient alternative for the diagnosis of suspected COVID-19 in developing countries.