Figure 1.

Cycle threshold (Ct) values are highly repeatable. Data points shown are Ct values for severe acute respiratory syndrome coronavirus 2 testing of pairs of nasopharyngeal samples obtained within either 6 hours (A) or 12 hours (B) of each other from the same patient, represented by the X and Y coordinates of each data point. Shaded areas indicate 95% confidence intervals for Theil-Sen linear regression fit. Abbreviations: CI, confidence interval; LR, linear regression fit; TS, Theil-Sen linear regression fit.