Fig. 1

Scatter plots of the Ct values for the three HPV channels. Panel a: all HPV-positive samples by both systems, results on cobas 4800 vs cobas 6800; linear correlation, R² = 0,78. Panel b: cobas 6800 intra-laboratory reproducibility; linear correlation, R² = 0,92. Panel c: cobas 6800 inter-laboratory reproducibility; linear correlation, R² = 0,92. Within each panel, the trendlines for the three channels overlapped. Ct = cycle threshold