Early stage cancer screening by detecting biomarkers in blood has been around for about 10 years now. Examples are Cologuard which detects colon cancer. Kaiser Permanente standardized on it in CA a few years ago. and EarlyCDT for lung cancer called , which I took years ago. There are are multiple companies that make these tests. the tests usually consist of some combination of samples from blood, saliva, stool, breath, urine, etc. Each cancer screen usually measures multiple biomarkers. Seldom is it an all or nothing result. It's more like you get a score for each molecule and then an oeral risk of having the cancer. As we have discovered new biomarkers for specific cancers, these test products have gotten more sensitive and selective as they add additional molecules to the set that constitutes the test for the given cancer. These tests are underutilized. They can detect cancer well before the soonest it can be seen in imaging.