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The American Thoracic Society committee on Proficiency Standards for Pulmonary Function Laboratories has recognized the need for a standardized reporting format for pulmonary function tests. Although prior documents have offered guidance on the reporting of test data, there is considerable variability in how these results are presented to end users, leading to potential confusion and miscommunication. A project task force, consisting of the committee as a whole, was approved to develop a new Technical Standard on reporting pulmonary function test results. Three working groups addressed the presentation format, the reference data supporting interpretation of results, and a system for grading quality of test efforts. Each group reviewed relevant literature and wrote drafts that were merged into the final document. This document presents a reporting format in test-specific units for spirometry, lung volumes, and diffusing capacity that can be assembled into a report appropriate for a laboratory's practice. Recommended reference sources are updated with data for spirometry and diffusing capacity published since prior documents. A grading system is presented to encourage uniformity in the important function of test quality assessment. The committee believes that wide adoption of these formats and their underlying principles by equipment manufacturers and pulmonary function laboratories can improve the interpretation, communication, and understanding of test results.

Background Accurate spirometry reference equations are essential for diagnosing and managing respiratory conditions in children. Although the GLI Global Equations have been proposed for general use, there were few Asian populations available for inclusion. This study aims to develop and validate spirometric reference equations for healthy Chinese children. Methods From May 2018 to May 2021, a cross-sectional study involving healthy Chinese Han children aged 4 to 18 years was conducted by 33 research centers across 24 regions in China. Participants were recruited directly from schools, and physical growth indices (height, weight) were measured. Spirometry tests were performed and demographic and medical history data were collected through questionnaires. New prediction equations were developed using multiple linear regression models with age, height, and weight as predictors. And comparisons were made with existing Caucasian and Chinese pediatric reference equations. Results Lung function was assessed in 8929 healthy Chinese Han children. Age, weight, and height emerged as strong predictors of lung function ( p  < 0.001), and sex-specific reference equations incorporating these factors demonstrated high accuracy in internal validation, yielding mean z-scores within a narrow range of -0.004 to -0.069. In comparison, the Zapletal equations overestimated FEV 1 and FEV 1 /FVC while underestimating other lung function parameters. Additionally, the GLI equations underestimated lung function parameters, including FEV 1 , FVC, and FEV 1 /FVC, for both boys and girls. Compared to previous Chinese studies, the z-scores in this study ranged from − 0.97 to 0.93, with some cases showing significant deviations, highlighting the limitations of existing equations. Conclusion This study developed new spirometry reference equations tailored for healthy Chinese children, with differences noted compared to existing equations. These equations reflect contemporary growth patterns and regional diversity in China, providing an additional option for clinical use. Trial registration NO.: ChiCTR: 1,800,019,029. Registered 22 October 2018.

Computed tomography (CT)-based lung density is used to quantitate the percentage of emphysema-like lung (hereafter referred to as percent emphysema), but information on its distribution among healthy nonsmokers is limited. We evaluated percent emphysema and total lung volume on CT scans of healthy never-smokers in a multiethnic, population-based study. The Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study investigators acquired full-lung CT scans of 3,137 participants (ages 54-93 yr) between 2010-12. The CT scans were taken at full inspiration following the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) protocol. \"Healthy never-smokers\" were defined as participants without a history of tobacco smoking or respiratory symptoms and disease. \"Percent emphysema\" was defined as the percentage of lung voxels below -950 Hounsfield units. \"Total lung volume\" was defined by the volume of lung voxels. Among 854 healthy never-smokers, the median percent emphysema visualized on full-lung scans was 1.1% (interquartile range, 0.5-2.5%). The percent emphysema values were 1.2 percentage points higher among men compared with women and 0.7, 1.2, and 1.2 percentage points lower among African Americans, Hispanics, and Asians compared with whites, respectively (P < 0.001). Percent emphysema was positively related to age and height and inversely related to body mass index. The findings were similar for total lung volume on CT scans and for percent emphysema defined at -910 Hounsfield units and measured on cardiac scans. Reference equations to account for these differences are presented for never, former and current smokers. Similar to lung function, percent emphysema varies substantially by demographic factors and body size among healthy never-smokers. The presented reference equations will assist in defining abnormal values for percent emphysema and total lung volume on CT scans, although validation is pending.

Background Reference values for lung volumes are necessary to identify and diagnose restrictive lung diseases and hyperinflation, but the values have to be validated in the relevant population. Our aim was to investigate the Global Lung Function Initiative (GLI) reference equations in a representative healthy Austrian population and create population-derived reference equations if poor fit was observed. Methods We analysed spirometry and body plethysmography data from 5371 respiratory healthy subjects (6–80 years) from the Austrian LEAD Study. Fit with the GLI equations was examined using z-scores and distributions within the limits of normality. LEAD reference equations were then created using the LMS method and the generalized additive model of location shape and scale package according to GLI models. Results Good fit, defined as mean z-scores between + 0.5 and -0.5,was not observed for the GLI static lung volume equations, with mean z-scores > 0.5 for residual volume (RV), RV/TLC (total lung capacity) and TLC in both sexes, and for expiratory reserve volume (ERV) and inspiratory capacity in females. Distribution within the limits of normality were shifted to the upper limit except for ERV. Population-derived reference equations from the LEAD cohort showed superior fit for lung volumes and provided reproducible results. Conclusion GLI lung volume reference equations demonstrated a poor fit for our cohort, especially in females. Therefore a new set of Austrian reference equations for static lung volumes was developed, that can be applied to both children and adults (6–80 years of age).

Grip strength is a measure of overall muscular strength and has been associated with disability, morbidity and mortality. Normative data are used to interpret an individual's grip strength measurements, but Canadian reference values are not available for a wide age range. The data pertain to 11,108 respondents aged 6 to 79 to the 2007-to-2013 Canadian Health Measures Survey, whose right-hand and left-hand grip strength were measured with a handgrip dynamometer. Quantile regression was used to develop reference equations for males and females for maximum, right-hand and left-hand grip strength for selected percentiles as a function of age, height and weight. Reference values for grip strength increased through childhood and adolescence, peaked around age 40, and then declined. Reference values were higher for males than for females; differences between the sexes were smaller during childhood than in adolescence and adulthood. Differences between reference values for maximum, right-hand and left-hand grip strength varied by age and sex. Based on a large, healthy, nationally representative sample, reference equations were developed for grip strength of Canadians from childhood to older adulthood. These equations can be used to determine the reference values that correspond to an individual of a given age, sex, height and weight.

Spirometry remains the cornerstone for diagnosing obstructive and restrictive lung disorders, yet the reference equation used to define “normal” function can significantly shift diagnostic outcomes, particularly in underrepresented populations. While the global lung function initiative (GLI) provides several equation sets, the implications of switching among them have not been fully explored in Middle Eastern populations. Therefore, the present study aimed to evaluate how diagnostic classification of respiratory disease changes when applying different GLI equations. This retrospective analysis included spirometric measures of 9731 participants obtained at a specialized allergy and asthma center in Anbar, Iraq. The cohort comprised both patients and individuals examined for other purposes, with 4341 males and 5390 females, and a markedly sex‐skewed smoking prevalence (28.4% in males vs. 1.6% in females). Predicted values, lower limits of normal (LLN), and z ‐scores were computed using the GLI Caucasian (GLI‐C), GLI Other or Mixed (GLI‐O), and the more recent race‐neutral GLI equation (GLI‐N). Diagnostic classifications for each equation were compared and stratified by sex and smoking status. GLI‐C equations consistently yielded higher predicted values and more negative z ‐scores. The GLI‐O identified more cases of obstruction, with the GLI‐N producing the largest proportion of normal classifications. Reclassification was common, particularly from restrictive to normal categories. The agreement between equations ranged from 0.80 to 0.94. The choice of reference equations significantly affects spirometric interpretation among this Iraqi cohort. It is recommended that laboratories and clinics explicitly report, justify, and standardize the selected reference set and prioritize prospective evaluations comparing GLI‐N, GLI‐O, and local equations with clinical correlates such as symptoms and outcomes to reduce misclassification across Middle Eastern populations.

Background: While peak in- and expiratory flow rates offer valuable information for diagnosis and monitoring in respiratory disease, these indices are usually considered too variable to be routinely used for quantification in clinical practice. Objectives: The aim of the study was to obtain reproducible measurements of maximal inspiratory flow rates and to construct reference equations for peak in- and expiratory flows (PIF and PEF). Method: With coaching for maximal effort, 187 healthy Caucasian subjects (20–80 years) performed at least 3 combined forced inspiratory and expiratory manoeuvres, until at least 2 peak inspiratory flow measurements were within 10% of each other. The effect on PIF preceded by a slow expiration instead of a forced expiration and PIF repeatability over 3 different days was also investigated in subgroups. Reference values and limits of normal for PIF, mid-inspiratory flow, and PEF were obtained according to the Lambda-Mu-Sigma statistical method. Results: A valid PIF could be obtained within 3.3 ± 0.6(SD) attempts, resulting in an overall within-test PIF variability of 4.6 ± 3.2(SD)%. A slow instead of a forced expiration prior to forced inspiration resulted in a significant (p < 0.001) but small PIF increase (2.5% on average). Intraclass correlation coefficient for between-day PIF was 0.981 (95% CI: 0.960–0.992). Over the entire age range, inter-subject PIF variability was smaller than in previous reports, and PIF could be predicted based on its determinants gender, age, and height (r 2 = 0.53). Conclusions: When adhering to similar criteria for the measurement of effort-dependent portions of inspiratory and expiratory flow-volume curves, performed according to current ATS/ERS standards, it is possible to obtain reproducible PIF and PEF values for use in routine clinical practice.

Background The Global Lung Function Initiative 2012 (GLI) reference values are currently endorsed by several respiratory societies but evaluations of applicability for adults resident in European countries are lacking. The aim of this study was to evaluate if the GLI reference values are appropriate for an adult Caucasian Swedish population. Methods During 2008–2013, clinical examinations including spirometry were performed on general population samples in northern Sweden, in which 501 healthy Caucasian non-smokers were identified. Predicted GLI reference values and Z-scores were calculated for each healthy non-smoking subject and the distributions and mean values for FEV 1 , FVC and the FEV 1 /FVC ratio were examined. The prevalence of airway obstruction among these healthy non-smokers was calculated based on the Lower Limit of normal (LLN) criterion (lower fifth percentile) for the FEV 1 /FVC ratio. Thus, by definition, a prevalence of 5% was expected. Results The Z-scores for FEV 1 , FVC and FEV 1 /FVC were reasonably, although not perfectly, normally distributed, but not centred on zero. Both predicted FEV 1 and, in particular, FVC were lower compared to the observed values in the sample. The deviations were greater among women compared to men. The prevalence of airway obstruction based on the LLN criterion for the FEV 1 /FVC ratio was 9.4% among women and 2.7% among men. Conclusions The use of the GLI reference values may produce biased prevalence estimates of airway obstruction in Sweden, especially among women. These results demonstrate the importance of validating the GLI reference values in different countries.