TY - JOUR T1 - Standardisation of lung function testing: the authors' replies to readers' comments JF - European Respiratory Journal JO - Eur Respir J SP - 1496 LP - 1498 DO - 10.1183/09031936.00130010 VL - 36 IS - 6 AU - M.R. Miller AU - J. Hankinson AU - V. Brusasco AU - F. Burgos AU - R. Casaburi AU - A. Coates AU - P. Enright AU - C. van der Grinten AU - P. Gustafsson AU - R. Jensen AU - N. MacIntyre AU - R.T. McKay AU - O.F. Pedersen AU - R. Pellegrino AU - G. Viegi AU - J. Wanger Y1 - 2010/12/01 UR - http://erj.ersjournals.com/content/36/6/1496.abstract N2 - To the Editors:A few questions have been raised following the publication in 2005 of the joint American Thoracic Society (ATS)/European Respiratory Society (ERS) series of documents on standardising lung function testing and these are answered below. The following questions and answers pertain to the standardisation document for spirometry 1. Start of test criteria Should blows be rejected solely on the basis of a poor back extrapolated volume (EV)? Reply Usually. The forced vital capacity (FVC) may be usable, but the forced expiratory volume in 1 s (FEV1) is likely to be falsely high or low. Rationale The acceptability criteria for spirometry were designed to help technologists improve the subject’s technique in order to get the best and most reliable result. EV is important for determining that a fast start to the blow was achieved and this is crucial for getting the best values for FEV1 and peak expiratory flow (PEF). End of test criteria In the original document, there was an error in table 5. Reply In table 5, the within-manoeuvre criteria for a satisfactory completion of a blow should have read “Duration of ≥6 s (3 s for children) and a plateau in the volume–time curve, or if the subject cannot or should not continue to exhale.” The original table had “or” in twice, whereas the accompanying text was correct, as above. Rationale The end of test (EOT) criteria are applied in order to ensure that efforts are made to achieve the best estimate of FVC. When a subject cannot meet the plateau criterion (<25 mL exhaled in the previous second of the blow) this may be for reasons other than premature volitional cessation of the blow. For example, in some young subjects or patients with a rigid chest wall, it is chest wall limitation that suddenly causes exhalation to stop 2 and it is difficult for … ER -