FIGURE 2: Linear regression curves to assess synthetic RNA copy number in fourplex rRT-PCR assays. (A–G) For each representative graph, four primer-probe sets within one reaction mixture were used to detect serial 10-fold dilutions of four synthetic RNA transcripts ranging from 10⁰ to 10⁹ copies per reaction. The y and x axes of each graph are the C_t values and the log of the input of synthetic RNA transcripts. respectively. For each fourplex reaction, R² indicates calculated linear coefficients and Eff. shows percentage of amplification efficiencies for each primer-probe set that is present with three other sets of primers and probes within one reaction master mixture. Fluorogenic probe color codes are as follows: blue, E Sarbeco; red, Orf1ab L; violet, N LSPQ; black, B2M; green, Spike 614G; orange, Orf1ab S; brown, Spike D614; pink, Spike 501Y; and gold, Spike N501. The graphs represent quantification of the results of three independent experiments.