Background Pulmonary function testing (PFT) is a key investigation in the evaluation of individuals with respiratory symptoms; however, the safety of routine and specialised PFT testing has not been reported in a large data set. Using patient safety incident (PSI) records, we aimed to assess risk of PFT and to characterise these events and any associated risk factors.

Methods In this single-centre audit, demographics and PSI data were collected and categorised for PFT performed between 1996 and 2016 and subdivided into cardiopulmonary or non-cardiopulmonary events. The severity of each PSI was rated using the NHS National Patient Safety Agency and any hospital admission reported.

Results There were 119 PSIs reported from 186 000 PFT; that is, 0.6 PSIs per 1000 tests. Cardiopulmonary PSIs were 3.3 times more likely to occur than non-cardiopulmonary (95% CI 2.17 to 5.12). Syncope was the most frequently occurring cardiopulmonary PSI. Cardiopulmonary exercise testing was associated with 2 PSIs per 1000 tests. PSIs necessitating hospital admission and/or emergency department attendance occurred approximately once every 10 000 tests and there was no PFT-associated mortality.

Conclusion Routine and specialised PFT is safe for patients, in the context of established screening preparticipation guidelines. In the event of a PSI, these are likely to be low risk of harm. Our findings highlight the most common PSIs encountered during PFT to facilitate risk reduction.