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

In Asthma, the levels of exhaled FeNO is correlated to sputum eosinophils particularly in the patient with poor controlled asthma or severe asthma. Moreover, the blood eosinophils had been studied that are also correlated to sputum eosinophils in similar patients group. According to well controlled asthma, althoug hin clinical practice guidelines recommend that the stepping down therapy should be considered to those patients due to the risks or costs of daily treatment, there is previous study has been shown that the airway hyperresponsiveness and sputum eosinophilia are predictors of loss of control during dose reduction. And, these tests are not readily available in primary care. However, there is limit number of clinical study to study the correlation of biologic markers among the patients with well controlled level before the stepping down management.