Table 2.

Approaches for vh-DNA detection in cfDNA.

Approaches	Coverage	Sensitivity	Price	Limitation	Applications
WGS	Unbiased	+	++++	Extremely high output is required due to the low amount of tumor-specific vh-DNA in total cfDNA	Primary tumor detection Treatment response monitoring MRD recurrence detection Determine the clonality of recurrence or metastasis Identify putative carcinogenic mechanisms
Capture-NGS	Probe-enriched vh-DNA	++	+++	Detection results greatly depend on probe design and hybridization stringency
ddPCR	Sequence-specific vh-DNA	++++	++	Sequence of target vh-DNA is required for the establishment of the assay Repetitive sequence in human genome might increase the difficulties in designing specific primer sets	Treatment response monitoring MRD recurrence detection
General PCR		+++	+