Table 1.

Features of techniques used to detect alterations from circulating tumoral DNA (ctDNA).

Techniques	Limit of Detection	Number of Targets	Type of Alteration Detection	Reference
PCR-based approaches
COLD-PCR	0.10%	1	SNV, indels	[34]
PNA-LNA	0.10%	1	SNV, indels	[35]
Probes improvement	0.01%–0.10%	1	SNV, indels	[36,37]
Digital PCR	0.01%–0.10%	1 to 4	SNV, indels, CNV	[38,39,40]
BEAMing	0.01%	1 to 20	SNV, indels	[41,42]
NGS-based approaches
Deep sequencing	0.02%	Panel	SNV, indels	[43]
Base position-error rate correction	0.003%	Panel	SNV, indels	[44]
TAm-Seq	2.00%	Panel	SNV, indels	[45]
CAPP-Seq	0.02%	Panel	SNV, indels, CNV, rearrangements	[46]
cSMART	0.01%	Panel	SNV, indels, rearrangements	[47,48]
Digital sequencing	0.10%	Panel	SNV, indels, CNV, rearrangements	[49]
Bias-Corrected Targeted NGS	0.10%	Panel	SNV, indels, CNV, rearrangements	[50]
SERS-nanotags	0.10%	1 to 3	SNV	[51]
UltraSEEK	0.10%	1 to 7	SNV, indels	[52]

PCR, polymerase chain reaction; COLD-PCR, coamplification at lower denaturation temperature PCR; PNA-LNA, peptide nuclei acid-locked nucleic acid; BEAMing, beads, emulsion, amplification, and magnetics; NGS, next-generation sequencing; TAm-Seq, tagged-amplicon deep sequencing; CAPP-Seq, cancer personalized profiling by deep Sequencing; SERS, surface-enhanced raman spectroscopy; UltraSEEK, high-throughput, multiplexed, ultrasensitive mutation detection; SNV, single nucleotide variation; CNV, copy number variation.