Reliability and Efficiency of Spirometry Results Before and After the Revision of Quality Control Criteria in Special Health Examination Institutions

This study evaluated the impact of revised spirometry quality control criteria on the test reliability and efficiency. One hundred and twenty spirometry records from 60 identical subjects were compared before and after the revision. The forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC) decreased by an average of 0.11 L (P<0.001), while the average number of test attempts and examination time decreased by 1.22 times and 1.58 minutes, respectively, indicating improved efficiency. Intraclass correlation coefficient analysis showed excellent repeatability for the FEV1 and FVC, with values exceeding 0.90. Agreement analysis using Cohen’s Kappa revealed high consistency, with κ=0.84 for the FVC and FEV1 grades and κ=0.87 for the interpretation. The proportion of A grades for the FVC increased from 68.3% to 98.3%, and all participants achieved an A grade in the FEV1. In contrast, the proportion of normal interpretations increased from 80.0% to 85.0% but the difference was not statistically significant (P=0.648). Bland-Altman analysis confirmed that all indicators were distributed stably within clinically acceptable limits. These findings show that the revised criteria effectively improve the reliability and efficiency of the spirometry performance and may provide fundamental evidence for establishing standardized testing guidelines and supporting the implementation of consistent spirometry systems in clinical practice.