A nurse is collecting data from an older adult client. Which of the following findings should indicate to the nurse that the client has a bladder infection?

Bladder infections (UTIs) in older adults often present atypically, with mental status changes like confusion being a hallmark due to systemic inflammation or bacteremia. WBC count of 9,000/mm³ is normal, not clearly indicating infection unless trending up; leukocytosis (e.g., >10,000) is more specific. Temperature of 37.3°C is a low-grade fever, possible but not definitive for UTI without other signs. Diminished reflexes relate to neurologic or age-related issues, not infection. Altered mental status, however, is a red flag older adults may lack classic UTI symptoms (e.g., dysuria), and confusion signals potential sepsis or delirium, per geriatric assessment guidelines. This finding warrants urgent reporting for urinalysis and treatment, preventing progression, making it the strongest indicator of a bladder infection.