The Porton Group and its partners filed a lawsuit claiming the Maplewood company failed to deliver on a promise to market a diagnostic test for hospitals. 3M made a multimillion-dollar deal to acquire the test in 2007, but much of the payout was tied to future sales. A year later, 3M had dropped the product, BacLite. The investment fund had sought $40 million in the suit. Both sides have claimed a victory in the case.