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

[884 P.2d 147] An additional analytical flaw, derived from the rationale of Gopaul v. Herrick Memorial Hosp., supra, underlies the decision below. In drawing the distinction between ordinary and professional negligence, the court in Gopaul observed that "[t]he need to strap plaintiff to the gurney while she was ill and unattended would have been obvious to all." (38 Cal.App.3d at p. 1007, 113 Cal.Rptr. 811.) In other words, it found that the circumstances did not require expert testimony to establish the appropriate standard of care. (Ibid.) This reasoning confuses the manner of proof by which negligence can or must be established and the character of the negligence itself, which does not depend upon any related evidentiary requirements.