What is the test for admitting expert opinion testimony in a medical malpractice case?

Expert opinion testimony is admissible if it is (1) "[r]elated to a subject that is sufficiently beyond common experience that the opinion of an expert would assist the trier of fact" and (2) "[b]ased on matter . . . that is of a type that reasonably may be relied upon by an expert in forming an opinion upon the subject to which his testimony relates . . . ." (Evid. Code, 801.) The jury need not be wholly ignorant of the subject matter of the opinion to justify its admission; even if the jury has some knowledge of the matter, expert opinion may be admitted whenever it would assist the jury. (People v. McAlpin (1991) 53 Cal.3d 1289, 1299-1300.) The opinion evidence is properly excluded when it would add nothing to the jury's common fund of information, i.e., when the subject of inquiry is of such common knowledge that a person of ordinary education could reach a conclusion as intelligently as the witness. (Id. at p. 1300.) A trial court's decision on the admission of expert testimony will not be disturbed on appeal unless " 'a manifest abuse of discretion is shown.' " (Id. at

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p. 1299.)