Table 3.

Comparison of different approaches for ctDNA detection

	NG-TAS	Digital PCR	TAm-Seq	Oncomine™ Breast cfDNA Assay
Approx. cost per sample (GBP)	3 × 10	2–3	10	200
Time (96 reactions)	7 h	3 h × 2	2 days	2 days
Number of amplicons	377	1	48	n/a
Amplicon size (bp)	< 160	n/a	< 200	< 170
Number of genes	20	1 (hotspot)	6	10
Choice of targets	Flexible	Limited	Flexible	Limited
Median depth	3064	770	650 (avg)	n/a
Limit of detection (%)	1–2	> 0.1	1–2	0.6–0.1
Library material as input	Yes	Not tested	Not tested	Not tested
Ideal input (ng)	3 × 10	2–5	50	20
Multiplex	8plex	No	No	n/a
Number of samples per sequence run	384	n/a	96	12
Platform	Fluidigm Access Array	Fluidigm qdPCR	Fluidigm Access Array	Ion Chef System
Sequencing	Illumina HiSeq 4000	n/a	Illumina GAIIx	Ion S5/S5XL™