Extended Data Fig. 4: Circulating tumor DNA cost and coverage analysis between Illumina and Ultima sequencing in a matched sample.

Areas under the curve (AUCs) are measured by calculating the area under a receiver operating characteristic curve comparing a given group (for example, Illumina 20x at 10−6 expected tumor fraction) to its platform and coverage-matched cancer-free control (for example, Illumina 20x, expected tumor fraction of 0). All AUCs at expected tumor fractions of 10−4 and greater were 1.00. Z-scores of a given sample are calculated against their coverage and platform matched cancer-free control (expected tumor fraction of 0).