How should the nurse explain normal lab results to the client's spouse?

The correct choice highlights the importance of normal lab results in the context of diagnosing Alzheimer's disease. When a nurse explains to the client's spouse that normal results help rule out other causes for the symptoms, it emphasizes that while the symptoms may be suggestive of Alzheimer's, the normal lab findings indicate that there are no other underlying medical conditions that could be contributing to those symptoms. This is a reassuring perspective, as it helps the family understand that certain other illnesses, which might mimic Alzheimer's symptoms, have been excluded through these tests.

This approach also underscores that Alzheimer's can only be definitively diagnosed through clinical evaluation, and lab tests primarily serve to eliminate other possibilities. By clarifying the role of the lab results in the diagnostic process, the nurse provides valuable information that can aid the spouse in coping with their loved one’s condition. Knowing that other potential causes have been ruled out allows families to focus more effectively on management and care strategies specific to dementia rather than getting sidetracked by fear of other health issues.