Fig. 3

Analytical performance of qRT-PCR and ddPCR for CCDC6::RET fusion detection. A Sensitivity of qRT-PCR and ddPCR assays. Measured values were plotted versus expected copies of gene fusion from serial dilutions. The black line represented the linear regression curve, and the outer dished lines represented the 95% confidence intervals (CIs). B Limit of detection (LoD) analysis for qRT-PCR and ddPCR by probit analysis. X-axis represented the expected concentration (copies/reaction). Y-axis represented the fraction of positive results at a certain concentration. The black line represented the dose–response probit curve, and the outer lines indicated the 95% CIs. C Variation of qRT-PCR and ddPCR. High concentration: expected 5000 copies/reaction. Low concentration: expected 500 copies/reaction. Three replicates were set at each concentration for calculating the intra-assay coefficient of variation (CV), and three different time points for the inter-assay CV