An increased proportion of eosinophils in sputum in the differentiated cell count.
Comment:
Sputum eosinophilia can be measured in various ways including measuing the mean percentage of eosinophils in the cell count of sputum induced by application of saline. The threshold chosen differs between studies, typically ranging from 1.25 to 3 percent. Increased sputum eosinophil counts may indicate a risk for severe chronic obstructive pulmonary disease or severe asthma.