What is the significance of a Forced Expiratory Volume in one second (FEV1) to Forced Vital Capacity (FVC) ratio of 78%?

From the Guidelines

A FEV1/FVC ratio of 78% is considered normal, indicating healthy lung function with good airflow through the airways. This ratio represents the proportion of your vital lung capacity that can be exhaled in the first second of forced expiration compared to the total amount you can exhale. Normal values typically range from 70-80% in adults, with values below 70% suggesting obstructive lung disease like asthma or COPD, as stated in the GOLD science committee recommendations for the use of pre- and post-bronchodilator spirometry for the diagnosis of COPD 1.

According to the GOLD 2025 report, the diagnosis of COPD should be considered in individuals with chronic respiratory symptoms and/or exposure to risk factors, and forced spirometry demonstrating airflow obstruction after bronchodilation is required to confirm the diagnosis using a threshold of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio <0.7 1. However, your value of 78% indicates that you do not meet this criterion, suggesting that you do not have COPD.

Some key points to consider:

• Maintaining good lung health through regular exercise, avoiding smoking, limiting exposure to air pollutants, and getting recommended vaccinations against respiratory infections remains important.
• If you had this test due to respiratory symptoms despite the normal ratio, other aspects of your pulmonary function tests or additional testing might be needed for a complete assessment.
• The GOLD 2025 report recommends using pre-BD spirometry to rule out COPD and post-BD measurements to confirm the diagnosis, which will reduce clinical workload and ensure that volume responders are not overlooked 2.
• Repeat spirometry should be guided by clinical status, with a suggested time frame of 3–6 months, especially if the initial post-BD FEV1/FVC ratio is between 0.60 and 0.80 2.

Overall, no specific treatment or medication is needed for this finding, but it is essential to continue maintaining good lung health and monitoring for any changes in respiratory symptoms or function.

From the Research

FEV1/FVC Ratio Interpretation

• The FEV1/FVC ratio is used to diagnose and classify chronic obstructive pulmonary disease (COPD) and other respiratory conditions 3, 4.
• A low FEV1/FVC ratio indicates an obstructive defect, which is defined as less than 70% or below the fifth percentile based on data from the Third National Health and Nutrition Examination Survey (NHANES III) in adults 4.
• The given FEV1/FVC ratio of 78% is below the normal range, indicating a potential obstructive defect.
• According to the study by 3, a FEV1/FVC ratio of less than 0.70 to 0.60 is classified as stage 2 COPD, indicating moderate airflow obstruction.

Classification of Airflow Obstruction

• The Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 1-4 classify the severity of airflow obstruction based on the FEV1% predicted (ppFEV1) 3.
• The new severity classification scheme, STAR, uses the FEV1/FVC ratio to classify the severity of airflow obstruction, providing a more uniform gradation of disease severity 3.
• The STAR classification system identifies a greater number of adults with stage 3/4 disease who would be eligible for lung transplantation and lung volume reduction procedure evaluations 3.

Diagnosis and Management of COPD

• COPD is a global public health problem, and its impact is increasing 5.
• Current treatment guidelines recommend the use of inhaled bronchodilators to decrease symptoms, improve lung function and quality of life, and prevent exacerbations 5, 6.
• Combination therapies, such as fluticasone propionate/salmeterol and tiotropium bromide, have been shown to be effective in improving lung function and reducing symptoms in patients with COPD 5, 6.