What is the test for a plaintiff to bring a personal injury action under a statutory change in the law governing personal injury actions?

As stated in an analogous case, also involving the application of a statutory change in the laws governing personal injury actions: " 'Logic dictates that a plaintiff cannot bring a cause of action until he knows or reasonably should know of his injury, and also knows or reasonably should know that the injury was caused by the wrongful acts of another. However, that does not mean that the plaintiff does not have an existing cause of action of which he is unaware.' " (Fetzer v. Wood (1991) 211 Ill.App.3d 70, 155 Ill.Dec. 626, 569 N.E.2d 1237.)