A comparison of diluent and methacholine challenge with spirometry and the body plethysmograph.

Bronchial reactivity to inhaled diluent and methacholine was determined for asthmatics using automated spirometry. These data were compared with challenge data from a matched group of asthmatics previously studied plethysmographically. High correlations were obtained between all indices both groups, suggesting that spirometry is adequate for the clinical characterization of the methacholine response.