Standard curves for quantification of EBV DNA. (A) Amplification plot for reactions with known starting amounts of pB-EBNA1 (an 8-log dilution from 5 ng to 0.5 fg, denoted by boxes next to the corresponding curves). Cycle number was plotted against change in normalized reporter signal (ΔRn). For each reaction, the fluorescence signal of the reporter dye (FAM) was divided by the fluorescence signal of the passive reference dye (ROX) to obtain a ratio defined as the normalized reporter signal (Rn). (B) Amplification plot of patients' plasma samples, demonstrating similar amplification profiles as the control plasmid shown in panel A. (C) Plot of standard curve of starting pB-EBNA1 amount against CT. Gray circles represent pB-EBNA1 standards as shown in panel A. Black circles represent patient samples. A standard curve was constructed for each assay. Note that as most samples showed moderate amounts of EBV DNA, patient samples tended to cluster on the left half of the graph. However, one patient with a high EBV DNA load is shown on the right half of the graph.
