CPFT Practice Exam 2025 – Complete Test Prep Guide

The diffusion capacity test, also known as the diffusing capacity of the lungs for carbon monoxide (DLCO), specifically measures how well oxygen and carbon monoxide are transferred from the lungs into the blood. During this test, a small amount of carbon monoxide is inhaled, and then the concentration of carbon monoxide in the breath is measured after a short period of time. This helps determine any potential impairments in the alveolar-capillary membrane, which can be affected by various conditions such as emphysema, pulmonary fibrosis, or interstitial lung disease.

Understanding the function of the lungs in terms of gas exchange is essential for evaluating overall respiratory health. The diffusion capacity result helps identify issues that may not be evident through other routine pulmonary function tests. This makes the diffusion capacity test a critical tool for clinicians in diagnosing and managing pulmonary diseases.

The other options provided focus on different aspects of lung function. For instance, the forced vital capacity test measures the amount of air a person can forcibly exhale, while residual volume measurements evaluate the amount of air remaining in the lungs after a full exhalation. Static compliance tests assess the elastic properties of the lungs and chest wall, which is different from the specific assessment of diffusion capability addressed by the diffusion capacity test. These tests