Coming together: the ATS/ERS consensus on clinical
pulmonary function testing
V. Brusasco*, R. Crapo#and G. Viegi"
European Respiratory Society (ERS) [7–9]. In addition, several
joint ATS/ERS workshops on pulmonary function testing have
been held and the resulting reports published [10, 11]. In 1995,
European scientists participated in the ATS updates of
standards for spirometry and single-breath carbon monoxide
diffusing capacity of the lung (DL,CO), but no joint statement
has been published by the two societies. Although generally
concordant, the spirometry and DL,CO guidelines published
separately by the ATS and the ERS differed in some aspects
that were of appreciable importance. Official guidelines for the
measurement of lung volumes were made available by the ERS
[7, 10], but not the ATS.
ince 1979, guidelines for standardising pulmonary
function tests have been published and updated by
both the American Thoracic Society (ATS) [1–6] and the
In recent years, global initiatives were undertaken for the
diagnosis and treatment of pulmonary diseases, and the
worldwide market for instruments to test lung function
widened considerably. This increased the pressure for more
uniform pulmonary function testing across the world, and
prompted the ATS and the ERS to appoint a joint Task Force to
provide new combined standards for clinical pulmonary
function testing, with the hope that they will be accepted by
other respiratory societies. A new Task Force on pulmonary
function testing, implemented by the Forum of International
Respiratory Societies (FIRS), has recently started its work
based on the ATS/ERS documents.
Our Task Force consisted of 19 scientists with recognised
expertise in pulmonary function testing. The group worked on
a ‘‘one-draft’’ system, in which each of five sections was
assigned to a small subgroup and eventually discussed by the
whole committee. There was a general feeling that previous
standards published by the two societies tended to be difficult
to use because of their overwhelming details and the lack of a
user-friendly indexing system. Therefore, one of the goals was
a change in format, including a more comprehensive indexing
system. We worked hard to make it easy for people to quickly
find what they need.
From its beginning in 2001 (a ‘‘new millennium project’’) to the
final approval in 2005, the Task Force met many times and had
some tough negotiations, both face to face and by e-mail or
conference call. We count it as one of our successes that all
participants stayed in the process until reasonable solutions
were found. As agreed, the new standards are due to appear as
a series in five consecutive issues of the European Respiratory
Journal, starting from the current one, which discusses general
considerations for lung function testing .
The spirometry section , mainly drafted by M.R. Miller and
J. Hankinson, is a model of clean user-friendly prose, which
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 instru-
ments. 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
The section on measurement of single-breath carbon mon-
oxide uptake in the lung (i.e. DL,CO) , mainly drafted by
N. MacIntyre, R. Crapo, G. Viegi, D.C. Johnson and C.P.M. van
der Grinten, stirred up some controversy first in the drafting of
the document and again in the comments received from
reviewers. The areas of concern were primarily related to
adjustments of DL,CO for lung volume (i.e. the use of DL,CO/
alveolar volume (VA)) and how to interpret unadjusted and
adjusted values if the decision was to adjust for lung volume.
All agreed that the DL,CO relationship to VA is complex, and
that the simple DL,CO/VA value does not necessarily ‘‘correct’’
for a reduced DL,CO in the setting of a comparably reduced VA.
There was also a significant discussion over how to deal with
adjustments for haemoglobin and carboxyhaemoglobin con-
centrations. Upon recognition that adjustments for haemo-
globin are under-utilised, we decided to adjust for these, but
the adjustments need to be made to the predicted rather than
the measured values. After the document was finalised, several
committee members were informally polled to find out how
they personally use DL,CO/VA. The responses mirrored the
review process. There was wide variation, ranging from ‘‘do
not use it at all’’ and ‘‘do not print it on the report’’ to saying
CORRESPONDENCE: V. Brusasco, Internal Medicine, University of Genoa, Viale Benedetto XV, 6,
Genova I-16132, Italy. Fax: 10 3537690. E-mail: email@example.com
*Internal Medicine, University of Genoa, Genova, Italy.#Pulmonary Division, LDS Hospital, Salt Lake
City, UT, USA."Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy.
Eur Respir J 2005; 26: 1–2
Copyright?ERS Journals Ltd 2005
EUROPEAN RESPIRATORY JOURNAL
VOLUME 26 NUMBER 1
something about it on every interpretation. This variation
amongst committee members suggests that more research on
the clinical utility of DL,CO/VA is required, to be possibly
included in a future version. The decision to use the term
DL,CO rather than the carbon monoxide transfer factor (TL,CO)
was not controversial until the document went for outside
review. Everyone on the Task Force understood that TL,CO is
more correct from a terminology and scientific standpoint, but
perhaps it was the long history of DL,CO and its common usage
that gave it the edge. Exercise and positional changes in DL,CO
were not addressed, although it was recognised that they may
provide an assessment of capillary recruitment and might,
therefore, be useful clinically, and this may be another addition
for a future version.
The lung volume section , mainly drafted by J. Wanger,
J.L. Clausen, A. Coates and O.F. Pedersen, 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 measure-
ments 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.
The section on interpretative strategies , mainly drafted by
R. Pellegrino, G. Viegi, P. Enright, V. Brusasco and R. Crapo,
generated rather strong controversy, but only in a couple of
areas. It emphasises the importance of selecting appropriate
reference values and lower limits of the normal range, and
provides a good listing of available reference studies with
suggestions for dealing with ethnicity. Nevertheless, the
committee realised that no single set of reference values can
be recommended and more work will be necessary in this area.
A detailed interpretative algorithm is presented, outlying the
position of each test for a state-of-the-art diagnostic procedure
in large hospital-based laboratories. Its use is not intended as
mandatory and simpler assessments of pulmonary function
are acceptable in different settings, keeping in mind the
limitations that are inherent to simplicity. The assessment of
reversibility of bronchoconstriction is covered in more detail
than in previous documents, with reminders that a number of
chronic obstructive pulmonary disease patients are more likely
to respond with improvements of lung volumes than forced
expiratory volume in one second.
As for any recommended standard, this one is not perfect, but
reflects the current knowledge in the field. Therefore, it should
be used as a guide for good clinical practice until changes are
made based on new scientific evidence. A future goal would be
the creation of standard pulmonary function reports, which
present the relevant data in a format that enables an ‘‘easy
interpretation and digestion of the information’’ .
On behalf of the whole group, we wish to thank E. Wouters
(Maastricht, Netherlands) for the initial input to the project and
B. Culver (Seattle, WA, USA) for the useful suggestions for
revision. We are also indebted to P. Silvi (Pisa, Italy) and
J. Embry (Salt Lake City, UT, USA) for editorial assistance.
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EUROPEAN RESPIRATORY JOURNAL