Standardisation of lung function testing: helpful guidance from the ATS/ERS Task Force

The American Thoracic Society and the European Respiratory Society have jointly issued a new revision of their guidelines for the performance of spirometry, lung volumes, and carbon monoxide transfer factor. These have been published as a series of documents in the European Respiratory Journal.^1–5 They contain much wisdom, some compromises, and a few new recommendations. Blood gases, sleep, exercise, and challenge testing have not yet been readdressed. This brief review highlights a few of the more important recommendations dealing with the performance and interpretation of the several tests.

GENERAL CONSIDERATIONS

This first chapter is essential reading for laboratory staff and sets standards for hygiene, calibration, quality control, and housekeeping. Observance of these standards will reassure research workers as well as clinicians.

SPIROMETRY

Peak flow is the topic of current research and the task force plans to introduce more stringent standards for home recording. It may be derived from the flow-volume plot or from a separate blow, ideally using a flow measuring device. The guideline emphasises the importance of rehearsal and the need to blow immediately after a full inspiration.

Relaxed expired and inspired vital capacity (EVC and IVC) have been rehabilitated, in spite of the fact that the various COPD guidelines—such as GOLD and others—chose to dispense with them for simplicity. When performing spirometry, the suggested method for EVC is to take the best of three measurements made before the forced expiratory tests, instructing the patient to speed the expiration only at the beginning and end of the blow. There is still no validated standard patter for this test; one suggestion might be “take a full breath in; breathe out gently but firmly”, going on to further encouragement after 2–3 seconds until flow is less than 0.25 l/s.

For forced vital capacity …