What pulmonary function tests (PFTs) are indicative of asthma?

The choice indicating obstructive pulmonary function test results is the correct answer because asthma is characterized by airway obstruction that can be identified through specific patterns in pulmonary function tests. In asthma, there are typically decreases in the Forced Expiratory Volume in one second (FEV1), Forced Expiratory Flow from 25% to 75% of the FVC (FEF 25-75), Peak Expiratory Flow Rate (PEFR), and often the Forced Vital Capacity (FVC) as well.

The reduced FEV1 reflects the primary impairment in airflow that occurs during an asthma attack, which results in the classic obstructive pattern seen on PFTs. Asthma is often reversible, meaning that bronchodilators will significantly improve these values, especially the FEV1, which is a hallmark in distinguishing asthma from other obstructive lung diseases like chronic obstructive pulmonary disease (COPD).

In contrast, restrictive lung patterns, which are often indicated by an increased FEV1 relative to a decreased FVC, suggest different pathologies such as interstitial lung diseases or pulmonary fibrosis and are not typically seen in asthma. Similarly, a normal FEV1/FVC ratio indicates proper airflow rates without obstruction, not corresponding with asthma, where