The Correlations of FeNO, Blood Eosinophils and Lung Function in Well-controlled Asthma

This is a single prospective trial. Enrollment will continue until 50 patients with well controlled asthma have been entered into this trial and have completed blood tests and spirometry. In this trial, the following parameters are to be evaluated: Blood eosinophils (absolute and relative) FeNO Pulmonary lung function test: FEV1, FVC, PF, MMEF 25-75%, % reversibility