What is the test for an expert testimony in a medical malpractice action?

"Whenever [a] plaintiff claims negligence in the medical context, the plaintiff must present evidence from an expert that the defendant breached his or her duty to the plaintiff and that the breach caused injury to the plaintiff." ( Powell v. Kleinman (2007) 151 Cal.App.4th 112, 123, 59 Cal.Rptr.3d 618.) Under Evidence Code section 720, "[a] person is qualified to testify as an expert if he has special knowledge, skill, experience, training, or education sufficient to qualify him as an expert on the subject to which his testimony relates." ( Evid. Code, 720, subd. (a).) "Against the objection of a party, such special knowledge, skill, experience, training, or education must be shown before the witness may testify as an expert." (Ibid. )