[Interpretation of spirometry: distinguishing prevalence from function].

Area of Science:

• Pulmonary Medicine
• Diagnostic Spirometry

Background:

• Accurate interpretation of spirometric data is crucial for diagnosing and managing lung diseases.
• Current methods for interpreting spirometry may benefit from refined approaches to distinguish disease prevalence from functional impairment.

Purpose of the Study:

• To propose an improved framework for interpreting spirometric data.
• To differentiate between the prevalence of lung conditions and the degree of functional impairment.

Main Methods:

• Utilizing reference values from the Global Lung Function Initiative, including predicted values and the fifth percentile.
• Evaluating spirometric parameters by mapping them onto a 0-100% scale of predicted values to assess functional impairment.

Main Results:

• The fifth percentile offers a statistically defined threshold for distinguishing normal from abnormal spirometric results.
• A scoring system based on the deviation from predicted values (0-100%) is suggested for quantifying functional impairment.

Conclusions:

• Distinguishing prevalence and function, alongside clinical context, is key for spirometry interpretation.
• The fifth percentile and a percentage-based impairment scale provide a more robust method for assessing lung function.