Recently, the American Thoracic Society has discussed the diagnosis, evaluation, pathogenesis, management, and unresolved issues of refractory asthma. The diagnostic criteria and evaluation methods for refractory asthma are described here. Diagnostic criteria The diagnosis of refractory asthma requires that at least 1 major criterion and 2 minor criteria be met simultaneously. Primary criteria: In order to control asthma to mild to moderate levels: 1. uninterrupted or largely uninterrupted (more than 50% of the time in 1 year) use of oral glucocorticoids is required. 2. high doses of inhaled glucocorticoids are required (see table). Secondary criteria: 1. daily need for bronchodilators in addition to inhaled glucocorticoids, such as: long-acting beta2 agonists, theophylline or leukotriene antagonists. 2. need for daily or almost daily use of short-acting beta2 agonists to control asthma symptoms. 3. persistent airway obstruction (FEV1 <80% predicted; >20% change in PEF per day). 4. at least 1 emergency room visit per year for asthma. 5. oral glucocorticoid dosing at least 3 times per year. 6. immediate worsening of symptoms on oral or inhaled glucocorticoid dose reduction ≤ 25%. 7. previous history of almost fatal asthma attacks. Evaluation of refractory asthma 1. pulmonary function measurements and evaluation of severity: 1. FEV1, peak expiratory flow rate, flow-volume loops measured before and after bronchodilator application. 1. total lung volume and residual air volume. 3. lung diffusion volume (adults only, usually not applicable to children). 2, Differential diagnosis of cough, dyspnea and wheezing: 1, chronic obstructive pulmonary disease (COPD); 2, pulmonary cystic fibrosis; 3, vocal cord dysfunction, or other upper airway obstruction; 4, obstructive sleep apnea syndrome (OSAS); 5, Churg-Strauss syndrome; 6, cardiac insufficiency; 7, allergic bronchial Pulmonary aspergillosis (ABPA). 3, Presence of concomitant factors aggravating asthma: 1, allergen skin test (atopic and allergic rhinitis). 2, sinus CT examination (sinus disease). 3, 24-hour esophageal pH measurement (GERD). 4, X-ray chest radiograph (pulmonary infiltrates, interstitial lung disease and pulmonary alveoli). 5, peripheral blood eosinophil count, Trichophyton tachyphylaxis skin test, blood IgE level ( Churg-Strauss syndrome or ABPA).