Quality of spirometry tests and pulmonary function changes among industrial company workers in Iran: a two-year before-and-after study following an intensive training intervention.

Background: Quality improvement, standardisation of spirometry testing, and interpretation of results are critically important in the occupational setting.

Aims: To determine the quality of spirometry tests and pulmonary function changes in two consecutive years among the personnel of an industrial company.

Methods: This study was performed in an oil refinery in Iran in 2011. Data on 1,004 male personnel were evaluated before and after a training course conducted according to the National Institute for Occupational Safety and Health guidelines. American Thoracic Society/European Respiratory Society guidelines were used for assessment of the acceptability and repeatability criteria.

Results: The most common error in the first year of evaluation was forced vital capacity >6 seconds or a 1 second plateau. Acceptability and proper interpretation significantly improved after the course (p<0.05), but repeatability did not change significantly (p>0.05).

Conclusions: The results of this study show that the validity and quality of spirometric tests conducted in the studied company in Iran were unacceptable, but these improved significantly after the training intervention. The study demonstrated the lack of a systematic guideline for conducting spirometry and interpreting the results in the occupational setting in Iran, and emphasises the need for a nationwide programme to improve the quality of spirometry tests in this setting.