A client with chronic obstructive pulmonary disease (COPD) reports increased shortness of breath with activity. Which test should the nurse schedule the client for evaluation of the symptoms?

A. Sweat test: The sweat test is primarily used to diagnose cystic fibrosis by measuring chloride levels in sweat. It is not relevant for evaluating shortness of breath or airflow limitation in adults with COPD. B. Spirometry: Spirometry is the standard pulmonary function test used to assess airflow obstruction, lung volumes, and the severity of COPD. It measures forced expiratory volume in one second (FEV₁) and the FEV₁/FVC ratio, providing objective data to evaluate worsening dyspnea and guide management of the disease. C. Antibody testing: Antibody testing is used to detect immune responses to infections or autoimmune disorders. It does not assess lung function or the degree of airflow limitation and is not indicated for evaluating COPD-related dyspnea. D. Lung biopsy: Lung biopsy is an invasive procedure reserved for diagnosing unexplained interstitial lung disease, tumors, or atypical lung pathology. It is not indicated for routine evaluation of symptom progression in COPD and carries unnecessary risk for this client.