All liquid biopsies are not tested in the same way. Comprehensiveness is one differentiating factor. Some liquid biopsies only test for a few specific genomic alterations. In this case it is usually done with “hot spot” testing, which tests 1‐10 specific mutations within the gene. Other liquid biopsies test across the whole exon of the gene to provide a more comprehensive picture.
Liquid biopsy tests also differ in the type of genomic alterations being interrogated. Most only do one or two of the following alterations: single nucleotide variants (SNVs), copy number variants (CNVs), fusions (re‐arrangements), and insertions/deletions (indels). In addition, some liquid biopsy tests are designed for only a specific type of cancer, whereas others are pan cancer.