Evaluation of reproducibility of a multibreath nitrogen washout test in normal subjects

The N2 washout test is a theoretically attractive test to be used for screening purposes. It does not require much cooperation but is sensitive enough to detect early disorders of intrapulmonary gas distribution and mixing. Conversely, in spite of computerization, it still has a not negligible cost, in terms of man-hours and materials. This cost should be weighted against the aimed precision of the results.