What is a liquid biopsy?
As a cancerous tumor grows, pieces can break off and circulate into your bloodstream. A liquid biopsy is a blood test that identifies those pieces. Unlike a surgical biopsy, liquid biopsies do not test tumor tissue, rather they test for evidence of a tumor. A circulating tumor cell (CTC) is a cancer cell from the tumor that is traveling in your bloodstream. Circulating tumor DNA (ctDNA) is a DNA fragment from the tumor cell. These pieces of your tumor provide genetic information about the cancer that can help your provider decide what course of treatment to approach.
How does a liquid biopsy work?
A liquid biopsy is performed by a simple blood draw. Once in the lab, a machine will separate the blood cells from the plasma to look for signs of CTCs or ctDNA in the plasma. If your blood sample is positive for CTCs or ctDNA, this will assist your provider in determining your cancer type.