Pulmonary Function Testing is primarily used to:

• A. Diagnose a specific respiratory disease.
• B. Assess the performance of the respiratory system structures.
• C. Visualize the lungs on X-ray.
• D. Measure respiratory rate.

Answer: (B)

Pulmonary Function Testing measures how well the lungs and chest work by quantifying volumes, capacities, airflow, and gas exchange. It assesses the performance of the respiratory system’s structures—airways, lung tissue, and chest mechanics—so you can gauge overall function rather than identify a single disease.

That’s why this is the best answer: PFTs provide objective data on how well the respiratory system is functioning, help distinguish patterns like obstruction or restriction, and monitor changes over time or in response to treatment. They aren’t imaging tests (they don’t visualize the lungs on an X-ray), they don’t measure respiratory rate, and they don’t diagnose a specific disease by themselves—the results must be interpreted in the context of symptoms and history.