The investment bank cut its price target on Quest's shares and noted recently passed legislation that it believes will put pricing pressure on the company.
Gainers in the index outpaced the decliners 19 to nine, and the index outpaced the Dow Jones Industrial Average and Nasdaq Biotechnology Index but lagged the Nasdaq.
The investment bank gave PerkinElmer an Outperform rating with a $114 stock price target and Hologic an In Line rating with a $55 stock price target.
BTIG gave Centogene a Buy rating, while SVB Leerink and Evercore ISI each gave the company an Outperform rating.
The investment banks cited the company's access to proprietary technology and the potential $5 billion market for Exagen's testing options as reasons for its Outperform rating.
The investment bank gave Danaher a Neutral rating and a $148 price target on the firm's shares, while it gave Agilent an Overweight rating with an $83 price target.
Overall, the share prices for 18 of the index's 27 companies fell month over month. Exact Sciences was the only firm whose share price improved in the double digits.
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.
Just five of the 28 firms in the 360Dx Index saw their share prices rise last month. Veracyte led the gainers, while Accelerate Dx had the sharpest decline.
Quest is expected to see incremental volume growth from the UnitedHealthcare contract and from a potential rise in M&A activity with outreach labs.