Paul Enright

This is a document produced by a joint ATS-ERS Task Force on lung function testing to provide new combined standards for Spirometry. It walks the reader through all the important elements of the test, from instrument to procedure quality control. One of the major steps forward is the recommendation that a standardised computer output format should be available on all instruments. This does not require equipment manufacturers to store their data in a specific format, but it does require them to provide a means of delivering the data in a standard way. This means that users won't be tied to a specific manufacturer in order to maintain their database structure. It also means that it will be relatively easy to write software to move spirometric data into healthcare databases where they can be used to monitor and guide therapy for patients with lung diseases. Such data can also be used for clinical research, including research into the efficacy of using pulmonary function tests in managing patients. Furthermore, International Organization for Standardization metrology terminology (www.iso.org) has been adopted.

The aim of the Task Force was to derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally. Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5-95 yrs. Lung function data were collated and prediction equations derived using the LMS method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family. After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals aged 3-95 yrs for Caucasians (n=57,395), African-Americans (n=3,545), and North (n=4,992) and South East Asians (n=8,255). Forced expiratory value in 1 s (FEV(1)) and forced vital capacity (FVC) between ethnic groups differed proportionally from that in Caucasians, such that FEV(1)/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed. Spirometric prediction equations for the 3-95-age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent and Arabic, Polynesian and Latin American countries, as well as Africa will further improve these equations in the future.

This is a document produced by a joint ATS-ERS Task Force on lung function testing to provide new combined standards for lung volume measurements. It largely reflects a document that was produced after an international workshop held in 1990, funded by the National Heart Lung and Blood Institute (NHLBI). That document was very large and never published in full print, but those interested in all the details can find it posted on the ATS website. In the new document, the relevant technical aspects and the limitations of the methods currently available for lung volume measurements are summarised in a user-friendly way. The position of lung volume measurements in the diagnosis of respiratory disorders and their cost-to-benefit ratio were probably the most controversial aspects of the Task Force.