The Battle Brewing Over Blood Tests for Cancer

Blood tests for cancer detection, known as liquid biopsies, can still be unreliable, but progress is being made. Competition between different diagnostics companies is also intensifying.

In July, the Food and Drug Administration approved Shield, a colorectal cancer blood test developed by the biotechnology company Guardant Health

. Shield became the first blood test approved by the FDA as a primary screening option for colorectal cancer that meets performance requirements for Medicare coverage, the company announced at the time. But its first mover