Detection of SARS-CoV-2 using non-commercial RT-LAMP regents and raw samples.

Alekseenko, A.; Barrett, D.; Pareja-Sanchez, Y.; Howard, R.; Strandback, E.; Ampah-Korsah, H.; Rovsnik, U.; Zuniga-Veliz, S.; Klenov, A.; Malloo, J.; Ye, S.; Liu, X.; Reinius, B.; Elsässer, S.; Nyman, T.; Sandh, G.; Yin, X.; Pelechano, V.

RT-LAMP detection of SARS-CoV-2 has been shown as a valuable approach to scale up COVID-19 diagnostics and thus contribute to limiting the spread of the disease. Here we present the optimization of highly cost-effective in-house produced enzymes, and we benchmark their performance against commercial alternatives. We explore the compatibility between multiple DNA polymerases with high strand-displacement activity and thermostable reverse transcriptases required for RT-LAMP. We optimize reaction conditions and demonstrate their applicability using both synthetic RNA and clinical patient samples. Finally, we validated the optimized RT-LAMP assay for the detection of SARS-CoV-2 in raw nasopharyngeal samples from 184 patients. We anticipate that optimized and affordable reagents for RT-LAMP will facilitate the expansion of SARS-CoV-2 testing globally, especially in sites and settings with limited economic resources.