Spirometry: how to evaluate the results?

   Introduction. The European Respiratory Society, the American Thoracic Society, and the Russian Respiratory Society are currently working on updating the technical standards and interpretive strategies for routine lung function tests. There is a search for recommendations for the best choice of reference values, the optimal limits of normal and severity grading of detected impairments. An important step in this work is the standartization of pulmonary function tests interpretation, including spirometry.   Aim. Review of existing concepts for the spirometry interpretation, according to new approaches to their quantitative and qualitative assessment. Materials and methods. The scientific publications on the PubMed and eLIBRARY.RU platforms were analyzed. The materials posted on the official websites of the European Respiratory Society, the Russian Respiratory Society, the American Thoracic Society and the Global Lung Function Initiativewere also used.   Results. A brief overview of the main reference values for spirometry is presented: the European Coal and Steel Community (1993), Global Lung Function Initiative (2012, 2021), R.F.Klement et al. (1986, 1991). The issues of defining the lower limit of the normal, diagnosing ventilatory impairments and assessing the severity of lung function reduction using the z-score and a percentage of the predicted value when analyzing the results of spirometry are considered.   Conclusion. The type of ventilatory impairment and severity should be presented in the spirometry interpretation just like the vital capacity assessment. The obstructive ventilatory impairment is generally diagnosed by spirometry, if the signs of restrictive or mixed patterns are present, it is recommended to determine the total lung capacity by body plethysmographymethod. Assessment of the limits of normal and the severity levels for any spirometry indices should be carried out using the z-score values.