Along with Exact, Natera and Qiagen saw sharp spikes in their stock prices, while Invitae and Opko Health each saw their share prices drop by more than 20 percent.
The decision is a quick reversal from a recent decision by the insurer not to cover fecal DNA testing and makes it the final major US insurer to cover Cologuard.
First quarter results that blew away analysts' estimates lifted Exact Science's stock, while Abbott's new deal with Alere sparked that firm's share price.
The company, which beat Wall Street expectations on the top and bottom lines, said completed Cologuard test volume rose 150 percent over Q1 2016.
The investment bank gave Exact Sciences' shares a price target of $30, and said it expects higher uptake of the Cologuard test and an increase in payor contracts.
The investment bank said Exact has the opportunity to book $4 billion to $5 billion in revenues a year from its colon cancer screening test Cologuard.
The company said it completed 82,000 Cologuard tests during the quarter, a 114 percent growth in test volume during the three-month period.
Several MDx firms recently touted BCBS's Evidence Street opinions on their tests as milestones, and Palmetto GBA's MolDx may soon be using its assessments.
Inclusion in the program would mark an important step in the company's quest to make Cologuard a standard of care for colon cancer screening.
Executives from Luminex and Exact Sciences provided updates on their companies at the 35th Annual JP Morgan Healthcare Conference in San Francisco.