What is the standard of care of a plaintiff in a medical negligence action?

It appears to be well settled in the authorities that, to establish a breach of the standard of care to support a claim for medical negligence, a plaintiff is required to lead expert evidence of a physician, practicing in the same field as the defendant, attesting to the defendant’s negligence.[see Kurdina v. Gratzer [2010] ONCA 288 at para. 2.] In Kurdina the Court of Appeal made it clear that to avoid summary judgment, the defendant is required to adduce some expert opinion evidence from a qualified practitioner in the same field as the defendant supporting her claim that the care she received fell below the applicable standard of care. Like this case, the plaintiff in Kurdina was self-represented and was suing for alleged negligence in psychiatric care provided to her by the defendants.