Patient must show that the physician-patient relationship existed in which the physician owed the patient a duty
Patients must show that the physician failed to comply with standards of the profession. For example a gynecologist has routinely taken Pap smears of a patient and then for whatever reason does not do so. If the patient then shows evidence of cervical cancer the physician could be said to have been derelict.
Patients must show that any damages were a direct cause of a physicians breach of duty. For example, if the a patient fell on the sidewalk and damaged her cast, she could not prove that the cast was damaged because it was incorrectly or poorly applied by her physician. It would be clear that the damage to the cast resulted from the fall. If, however, the patient's leg healed incorrectly because of the way the cast had been applied, she might have a case.