Table 4.

Concordance of plasma ctDNA by NGS and standard tissue RAS testing (n = 30).

	Tissue RAS Status
	RAS	Mutant	WT	Total	PPA	NPA	OPA
Plasma ctDNA RAS status by NGS	Mutant	13	1	14	100 × 13/16 = 81.2%	100 × 13/14 = 92.8%	100 × 26/30 = 86.7%
	WT	3	13	16
	Total	16	14	30

ctDNA: circulating tumor DNA; dPCR: digital PCR; NGS: Next-generation sequencing; WT: Wild type; PPA: Positive percent agreement; NPA: Negative percent agreement; OPA: Overall percent agreement.