Final answer:
The appropriate nursing response would be to refuse to provide any information to the caller, citing rules of confidentiality and the legal requirement under HIPAA to protect patient information.
Step-by-step explanation:
The appropriate nursing response to a call asking if an individual has been a client in a facility would be to refuse to give any information to the caller, citing rules of confidentiality. This is because maintaining confidentiality is not only an ethical obligation for healthcare providers, but it is also a legal requirement under the Health Insurance Portability and Accountability Act (HIPAA), which sets standards for protecting patient information. By refusing to provide any information, the nurse ensures that the patient's privacy rights are respected.