Guardant Health is a precision oncology company that provides blood and tissue-based tests, along with AI-powered analytics, to support cancer care across screening, early detection, and treatment selection. The company's core offerings include liquid biopsy tests like Guardant360 CDx for tumor profiling and therapy selection, Shield for colorectal cancer screening, and Guardant Reveal for minimal residual disease detection, as well as tissue-based multiomics testing and biopharmaceutical research tools. Revenue is generated through reimbursement by commercial insurers, government payers, and direct patient payment, supplemented by collaborations with drug development companies that use the company's testing services for biomarker discovery and clinical trial support; the company serves oncologists, cancer centers, hospitals, health systems, and biopharmaceutical firms primarily in the United States with growing international presence.