Table 3.

The comparison of various ctDNA detection methods.

Type	Technique	Stability	Sensitivity	Cost	Target	Features
ARMS-based	ARMS	Mediate	Low	Low	Single gene mutation	Convenient, easy-operation
	Super-ARMS					Higher sensitivity than ARMS
dPCR-based	ddPCR	High	High	Low	Single gene mutation	Available for the clinic
	BEAMing					Definite ctDNA-quantification
NGS-based	TAM-Seq	High (influenced by laboratory level)	High	High	Multiple gene mutations	Less cost and time, and lower sensitivity than other NGS-based methods
	Safe-SeqS					Identification of rare genetic mutations
	CAPP-Seq					“Filter”; relatively high sensitivity
	iDES					Higher sensitivity than CAPP-Seq
	TEC-Seq					Deep sequencing; potential in the early-diagnosis when no symptoms occur
Mass spectrometry	MassARRAY	–	Mediate	Mediate	Multiple gene mutations	Less range than NGS-based methods
Others	EFIRM	–	Mediate	Low	Multiple gene mutations	Short time; easy-operation

ARMS, amplification refractory mutation system; PCR, polymerase chain reaction; ddPCR, droplet- based digital PCR; BEAMing, breads, emulsification, amplification and magnetics; TAM-Seq, tagged-amplicon sequencing; Safe-SeqS, safe sequencing system; CAPP-Seq, cancer personalized profiling by deep sequencing; iDES, integrated digital error suppression; TEC-Seq, targeted error correction sequencing; EFIRM, electric field-induced release and measurement.