MSFinals-5841

A 55-year-old female presents with worsening dyspnoea and the need to sit down frequently. She has had no other health issues. The patient works in an office.
During the physical examination, the patient is found to have clubbing and fine end-inspiratory crackles upon auscultation. A chest X-ray reveals diffuse reticulonodular shadows, particularly in the lower lobes.
What is the most suitable next step in managing this patient?