Five of these targets are on-label approved biomarkers for FDA-approved therapies. Any of these or other changes could substantially impact our revenues and increase costs. We also may be subject to additional unannounced inspections. Most Class I products are exempt from the premarket notification requirements. As a practical matter, clearance often takes longer, and clearance is never assured. If it is not, the agency will refuse to file the PMA. An RUO device is an IVD that is in the laboratory research phase of development. RUO devices must bear prominent labeling stating: "For Research Use Only. The performance characteristics of this product have not been established." In January 2018, we received EAP designation from the FDA for our Guardant360 test. Since its enactment, there have been efforts to repeal all or part of the ACA. We are dependent on third parties for the collection of blood samples for our tests. Clinical data is sometimes required to support a substantial equivalence determination. Such appeals may not result in payment. To maintain this certificate, we are subject to survey and inspection every two years. Such a loss of patent protection could have a material adverse impact on our business. Our licensed or acquired technology may lose value or utility or over time. We are subject to counterparty risk with respect to the 2027 Note Hedge transactions. We cannot predict the extent to which the Guardant-19 test will be used by third parties.