Final answer:
The most appropriate nursing diagnosis for the client expressing concern over a scheduled intravenous pyelogram is anxiety related to unfamiliarity with the procedure.
Step-by-step explanation:
The most appropriate nursing diagnosis for the client expressing concern over a scheduled intravenous pyelogram is Anxiety related to unfamiliarity with the procedure. The client's statement indicates fear or worry about the unknown aspects of the procedure, which can be classified as anxiety. Other options, such as fear of complications or lack of knowledge, might also be valid concerns, but they are not as directly related to the client's statement as anxiety.