Why are percent predicted values significant in interpreting PFT results?

Percent predicted values are significant in interpreting pulmonary function test (PFT) results because they provide a benchmark based on key demographic factors, including age, gender, height, and ethnicity. When PFT results are expressed as percent predicted, they allow for meaningful comparisons between an individual's test results and what is considered normal for that specific population. This standardization is essential for accurately assessing lung function, as normal values can vary significantly due to these demographic factors.

Using percent predicted values enables healthcare providers to evaluate whether a patient's lung function is above or below the expected range for their demographic group. For example, a person may have a lower absolute value for lung function simply due to being shorter or older, and percent predicted values help to contextualize these results appropriately.

While consideration of ethnic groups and other variables are important, the core reason for percent predicted values lies in their ability to refine the interpretation of results by aligning them with a relevant normative framework. This way, it enhances the precision of clinical assessments regarding respiratory health.