What is the test for maintaining a cause of action for fraudulent concealment?

To maintain a cause of action for fraudulent concealment, a plaintiff must establish that a defendant had a duty to disclose. Fraudulent concealment can occur where a defendant " 'actively conceals a material fact from plaintiff' " or " 'makes partial representations but also suppresses some material facts,' " but only if "some other relationship between the plaintiff and defendant" gives rise to a duty to disclose. (LiMandri v. Judkins (1997) 52 Cal.App.4th 326, 336-337 (LiMandri).) The requisite relationship "can only come into being as a result of some sort of transaction between the parties." (Id. at p. 337.) For example, "a duty to disclose may arise from the relationship between seller and buyer, employer and prospective employee, doctor and patient, or parties entering into any kind of contractual agreement." (Ibid.)