The investment bank gave the liquid biopsy company a price target of $90 and said that it views Guardant as the field leader.
Canaccord said Meridian Bioscience's preannounced second quarter top-line miss and expected ongoing weakness in its MDx business were among the reasons for the downgrade.
UBS granted Agilent a Buy rating and a $92 price target, and Qiagen a Neutral rating with a $42 price target.
The company is currently conducting clinical studies to validate AlloSure's technology — which underlies its kidney transplant test — in lung transplant patients.
The firm's diagnostics and genomics group saw a 13 percent year-over-year revenue increase in the first quarter.
The investment bank said the company is strongly positioned as a leader in the transplant diagnostics market with tests that serve an unmet need.
An analyst said the DetermaVu test could potentially be best in class for lung cancer diagnosis and that CMS could begin reimbursing for it in late 2020.
The firm said net product revenues fell 11 percent year over year in the fourth quarter.
UBS initiated coverage of Quest with a Neutral raing and a $90 price target on its shares. It gave LabCorp a Buy rating and a $169 price target.
The improvement in the 360Dx Index was modest compared to 2017, but it still outpaced the broader markets, which fell dramatically in the last month of the year.