Bronchial asthma cannot be detected by means of a blood test. Bronchial asthma is a chronic respiratory disease influenced by a combination of host and environmental factors, and its occurrence can lead to death. A definitive diagnosis of bronchial asthma is the basis for the implementation of the next step in the treatment, so individuals need to go through a scientific examination in order to confirm the diagnosis of the disease. However, a blood test can not detect bronchial asthma, because the diagnosis of bronchial asthma is made through the relevant signs and symptoms, the objective examination of the variable airflow limitation (realized by pulmonary function tests), and the exclusion of wheezing, shortness of breath, and tightness of the chest caused by other diseases. Once an individual meets the diagnostic criteria for bronchial asthma through examination, a diagnosis of the disease can be made. And individuals who are diagnosed with bronchial asthma must be treated aggressively.