Asthma is a chronic inflammatory airway disease. Significant heterogeneity exists in the clinical manifestations and treatment responses in these patients. Metabolomics is a large-scale approach to monitoring as many as possible of the compounds involved in cellular processes in a single assay to derive metabolic profiles. Compared with genomics or proteomics, metabolomics reflects changes in phenotype and therefore function. Up to now, few studies have evaluated the role of metabolomic analysis in the diagnosis and prognostic evaluation of airway disorders. Collection of exhaled breath condensate (EBC) is a newly developed, noninvasive method that may allow clinicians and researchers to assess biochemical profiles in the alveolar lining fluid. This study will apply metabolomics to examine the biomarkers in the EBCs, serum and urine specimens in adult asthmatics.

The aims of this study are: 1. Metabolomic profiling of the exhaled breath condensate (EBC), serum and urine specimens in adult asthmatics; 2. Correlation between metabolomic profiles of these specimens with the severity and control of asthma; 3. Comparing metabolomic profiles in asthmatics with different phenotypes and endotypes; 4.Comparing metabolomic profiles obtained from asthmatics during stable and acute exacerbation periods; 5. Comparing metabolomic profiles in asthmatics before and after inhaled corticosteroid therapy.

Inclusion Criteria:

1. 20-90 years
2. Diagnosis of asthma based on the GINA guideline

Exclusion Criteria:

1. Patient with cancer
2. Patient with long-term ventilator use

Adult asthmatics