UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 _____________________ FORM 10-Q _____________________ (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2019 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38683 _____________________ GUARDANT HEALTH, INC. (Exact Name of Registrant as Specifi ...