SAN FRANCISCO – Guardant Health Inc. has set the standard for liquid biopsy. That success has catapulted the Redwood City, Calif.-based company from an IPO in the fall of 2018 to a current valuation in excess of $7 billion. It has made its name – and much of its revenue – with its Guardant360 test, a molecular diagnostic test that assesses 74 cancer-related genes from the circulating tumor DNA to aid in designing the best treatment for advanced cancer patients with solid tumors.