Which of the following confirms the diagnosis of asthma or airway hyperresponsiveness?
Exercise-induced bronchospasm in which FEV1 or FVC is ≥ 15% after exercise.
Improvement of FEV1 and FEV1/FVC by ≥ 12% or 200 mL with the administration of a bronchodilator.
At least a 20% drop in FEV1 from baseline (PC20) after provocative testing with methacholine, a nonspecific bronchial irritant.
Eucapnic voluntary hyperventilation (EVH) showing a marked decrease in FEV1.
