This image provided by Guardant Health in March 13, 2024, shows a vial for their colon cancer blood test, Shield. According to a study published Wednesday, March 13, 2024, in the New England Journal of Medicine and sponsored by Guardant Health, the test performed well, further expanding screening options for a leading cause of cancer deaths. The test missed some cancers and won’t replace colonoscopy, the gold standard test. (Guardant Health via AP)