A 53-year-old man presents for evaluation of progressive shortness of breath. His symptoms are insidious in onset and he reports no cough, sputum, or chest discomfort. His past medical history is significant for well-controlled hypertension and type 2 diabetes. He is a lifetime nonsmoker and has no history of occupational exposure to inhaled organic or inorganic particles. Pulmonary function tests reveal a restrictive defect, and a high-resolution CT suggests pulmonary fibrosis. Which of the following is the most likely role of transbronchial biopsy in this condition?