[Functional approach to asthma (author's transl)].

The different pulmonary function tests which enable the diagnosis of asthma and its functional criterium, reversible bronchial obstruction, are reviewed. It is our opinion that in epidemiology where the diagnosis should be made "on the spot" in a simple, rapid and non-aggressive manner, the most appropriate tests are the following: the FEV1 or other forced expiration parameters, to which could be added the measurements of closing volume, the slope of phase III, and/or flow-volume curves using two gas mixtures. The modifiers of bronchomotricity could confirm the reversible nature of the bronchial obstruction.