Figure 1
From: Reference values for methacholine reactivity (SAPALDIA study)
Graphic representation of the relationship between the two-point dose response slope and PD20. This figure shows the relationship between the two-point dose response slope and PD20. The horizontal line drawn at a slope of 2.39% decrease/μmol represents the "cut-off" threshold commonly used to define bronchial hyperreactivity (20% decrease of FEV1 after a cumulative methacholine dose of ≤ 2 mg).