What is the test for a medical malpractice claim in negligence rather than battery?

Since Reibl v. Hughes, supra it has been clear that a failure to disclose gives rise to a claim in negligence rather than battery unless the patient’s consent was obtained by means of a misrepresentation or fraud: … 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 due 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 (at pp. 891-892).