What is the test for consent in medical malpractice cases?

In Reibl v. Hughes, 1980 CanLII 23 (SCC), [1980] 2 S.C.R. 880 at 891, Laskin C.J. stated: I can appreciate the temptation to say that the genuineness of consent to medical treatment depends on proper disclosure of the risks which it entails, but in my view, unless there has been misrepresentation or fraud to secure consent to the treatment, a failure to disclose the attendant risks, however serious, should go to negligence rather than to battery. Although such a failure relates to an informed choice of submitting to or refusing recommended and appropriate treatment, it arises as the breach of an anterior duty of care, comparable in legal obligation to the duty of due care in carrying out the particular treatment to which the patient has consented. It is not a test of the validity of the consent.