In diagnostic medicine, biopsies, where a sample of tissue is extracted for analysis, is a common tool for the detection of many conditions. But this approach has several drawbacks—it can be painful, doesn't always extract the diseased tissue, and can only be used in a sufficiently advanced disease stage, making it, in some cases, too late for intervention. These concerns have encouraged researchers to find less invasive and more accurate options for diagnoses.
source https://phys.org/news/2021-02-advance-simple-inexpensive-diagnostic-blood.html
