Fig. 3.

SARS-CoV-2 detection in wastewater using primers-probe sets Improved N3 and CDC's N2. For each sample out of 148 different samples in September–December 2020, ΔCt was calculated. ΔCt is comprised from reduction of the resulted Ct for Improved N3 from the resulted Ct for CDC's N2. For samples where CDC's N2 resulted in a signal while Improved N3 did not, meaning only CDC's N2 detected, an arbitrary value of −5 was assigned and colored in blue. For samples where Improved N3 resulted in a signal while CDC's N2 did not, meaning only Improved N3 detected, an arbitrary value of +5 was assigned and colored in red. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)