Spirometry: quantitative test criteria and test acceptability.

Quantitative test criteria have been developed to assess the acceptability of spirometric tracings. Most automated spirometers have been programmed with the criteria in order to assist in data collection. These instruments compare computed parameters from the collected tracings with the criteria and, after 3 acceptable FVC maneuvers have been collected, print out a statement indicating that "tests meet acceptability criteria." Technicians, nurses, and even their medical supervisors are beginning to rely on these statements as assuring overall test quality. However, a review of actual curves indicates that unacceptable results can be obtained from tests that comply with these standards. Although quantitative test criteria are a positive step toward quality assurance, they should be treated as they were developed, as "minimum" criteria. All curves should be inspected for visible defects, especially if the results are used to follow subjects longitudinally.