COPD diagnosis related to different guidelines and spirometry techniques.

The aim was to compare the diagnosis of COPD among smokers according to different international guidelines and to compare the outcome when using slow (SVC) and forced vital capacity (FVC). In order to find current smokers a questionnaire was sent to persons who had been on sick leave for more than two weeks. Those who smoked more than 8 cigarettes per day were invited to perform a spirometry.