PALO ALTO, Calif. & SECAUCUS, N.J.--(BUSINESS WIRE)---- $GH--Guardant Health, Inc. (Nasdaq: GH), a leading precision oncology company, and Quest Diagnostics (NYSE: DGX), a leader in diagnostic information services, today announced a broad strategic collaboration to make Guardant's Shieldâ... blood- based screening test available to physicians and patients served by Quest in the United States. Shield is the first and only blood test to receive full FDA approval as a primary screening option for colorectal c. ...