CPFT Practice Exam 2026 – Complete Test Prep Guide

The FEV1/FVC ratio is a crucial parameter used in pulmonary function testing to assess lung function, particularly in distinguishing between obstructive and restrictive patterns of lung disease. The correct equation for calculating the FEV1/FVC ratio is the FEV1 value divided by the FVC value, expressed as a percentage. Therefore, the correct formulation is FEV1 divided by FVC, multiplied by 100.

This ratio helps healthcare providers evaluate how much air a person can exhale in one second (FEV1) compared to the total amount of air they can exhale after taking a deep breath (FVC). A low FEV1/FVC ratio is indicative of obstructive lung diseases, such as asthma or COPD, where the ability to expel air quickly is impaired.

The formulation aligns directly with the accepted definition of the FEV1/FVC ratio in respiratory medicine, making it essential for accurate interpretation of pulmonary function tests. Understanding this relationship is crucial for effectively diagnosing and managing various respiratory conditions.