[The reference values selection and validity check also are a spirometry quality issue].

Spirometric measurements are widely used for routine clinical assessment of workers with occupational exposures to bronchial irritants or sensibilizing agents, however their interpretation requires appropriate reference values for predicting normality. We studied 1319 subjects 18-25 years old (754 males--57.1% e 565 females--42.9%) with BAIRES-Biomedin spirometer and observed values were compared with different reference equations for italian workers: CECA 1971, ERS 1993, Scotti and coll. 1986, Pistelli and coll. 2000. All reference equations studied have significantly differences for one or more index, even if the observed values are all near to 100% of predicted values. The ERS 1993 reference values were always statistically different from observed values. In conclusion we suggest prudence in interpreting spirometry in young people and we hope the identification of new spirometry reference values for Italian people.