Final answer:
A patient's room number is not considered an acceptable identifier for administering medications, blood, or blood components; instead, unique identifiers like a patient's name and medical record number should be used.
Step-by-step explanation:
The question asks which of the following is not an acceptable identifier under the requirement that two patient identifiers be used when administering medications, blood, or blood components. The acceptable patient identifiers typically include the patient's full name and an assigned identification number such as a medical record number. Therefore, a patient's room number or a patient's telephone number is not considered an acceptable patient identifier for this purpose, as room numbers can change and telephone numbers may not be unique to an individual. In most healthcare settings, a patient's room number is specifically discouraged from use as an identifier to prevent errors.