ABSTRACT
The following strategy offers an approach to medical interpretation of a set of lung function data. In practical terms, interpretation of the data is guided heavily by the clinician's first impression of the patient, and the suspected diagnosis. An obstructive defect is present, suggestive of airway disease, possibly caused by chronic obstructive pulmonary disease (COPD), asthma, bronchiectasis or rarely, large airway obstruction or obliterative bronchiolitis. Patients with large airway obstruction are prone to sudden deterioration, so some urgency may be required, depending upon the time course of events and severity of obstruction. If an obstructive defect persists without significant response to bronchodilator, then a cause of fixed airway obstruction should be sought. Elevation of TLCO and KCO occurs in alveolar haemorrhage, although these patients are often too unwell to complete pulmonary function testing, and the window of opportunity to identify acute pulmonary haemorrhage by measurement of TLCO is often short.
