Certified Pulmonary Function Technologist (CPFT) Practice Exam

What is an important indicator for obstructive disease in lung function testing?

1. Increased DLCO

2. FEV1

3. FVC

4. FEV1%

The correct answer is: FEV1%

The FEV1%, or Forced Expiratory Volume in one second as a percentage of the Forced Vital Capacity (FVC), is a crucial indicator for obstructive lung diseases in pulmonary function testing. In individuals with obstructive conditions, such as asthma or chronic obstructive pulmonary disease (COPD), there is a reduction in the ability to expel air from the lungs quickly, resulting in a lower FEV1 value relative to the FVC. A decreased FEV1% indicates that a larger proportion of the total lung capacity is trapped in the lungs, which is characteristic of obstructive diseases. A normal or increased FEV1% would typically suggest that obstructive disease is less likely. In contrast, while FEV1 is an important metric by itself in assessing lung function, when interpreted with respect to FVC, it provides deeper insight into the presence of obstruction. The other indicators, such as DLCO and total lung capacity measures, reflect different aspects of lung function and do not specifically highlight the restrictive nature of airflow obstruction like FEV1% does.