Lung function testing and interpretation

Abstract

Pulmonary function tests (PFTs) are non-invasive tests that indicate how well or poorly an individual’s lungs are functioning. PFTs aid the diagnoses of symptomatic disease, screen for early asymptomatic disease, monitor any response to pharmacological therapy, and provide a prognosis for a known disease. PFTs can only provide a physiological diagnosis and not a clinical diagnosis of pulmonary disease. It is important to recognise that a PFT is not a standalone test. A combination of the clinical picture of a patient with other diagnostic tests (arterial blood gases, chest X-rays, etc.) must be made to make a clinical diagnosis of pulmonary disease, particularly if there is a high index of suspicion for disease but PFTs are interpreted as normal.¹