Credit: Viecelli et al, 2020 (PLOS ONE, CC BY 4.0)
Quantification of SARS-CoV-2 by ddPCR.
A) The graph shows the linear relationship between the expected and the observed concentrations using serial dilutions of the SARS-CoV-2 reference in the two experiments. B) The histogram reports the concentrations of the SARS-CoV-2 reference obtained in the first (light grey) and second (dark grey) experiment. In particular, each expected concentration was tested in two independent experiments each led in duplicate (the lowest concentration, 2 copies per reaction, led in quadruplicate).