Figure 2.

Conceptual framework for the use of fractional exhaled nitric oxide (Fe_NO) testing to guide treatment decisions for individuals with asthma. The decision to act on an individual Fe_NO value in an individual patient requires that the clinician combine clinical judgments based on the perceived probability of benefit, with particular attention being given to the key outcome measures such as exacerbation risks that were assessed in this guideline. As the level of Fe_NO increases in value, the specificity for a step up in therapy increases, whereas accepting lower values of Fe_NO to make treatment decisions places a higher value on the sensitivity to detect the possibility that a step up in therapy may impact asthma control.