Is methacholine challenge sufficient to rule out bronchial hyperresponsiveness in patients with suspected asthma?

Fluticasone propionate in clinically suspected asthma patients with negative methacholine challenge test

“…It is suggested that bronchodilator/steroid inhalers should be withheld in clinically suspected asthma patients with negative methacholine challenge test (CSA/MCT2) and they reexamined for underlying pathology behind the individual's asthma-like symptoms (5,8). However, asthmatic features such as expiratory nitric oxide level 30 ppb, positive adenosine challenge test and low Asthma Control Test (ACT) score were reported in 20% of clinically suspected asthma patients with negative MCT (9). Also, physician-based asthma diagnosis with symptom relief by means of bronchodilator or inhaled steroid was reported in some patients with a negative MCT (10,11).…”