In PFT, what does "reversibility" generally refer to?

In pulmonary function testing (PFT), "reversibility" primarily refers to the improvement in lung function following the administration of bronchodilator medication. This concept is particularly important when evaluating patients for conditions such as asthma or chronic obstructive pulmonary disease (COPD). When clinicians observe a significant increase in key measurements, such as forced expiratory volume in one second (FEV1) or forced vital capacity (FVC), after bronchodilator use, it indicates that the airflow obstruction is at least partially reversible. This is a critical aspect in differentiating between various respiratory disorders and in determining the efficacy of asthma management.

Being able to quantify this reversibility helps guide treatment decisions and elucidates the pathophysiological mechanisms at play in the patient's condition.