Worldwide practices in pulmonary function test reporting after lung transplantation

Abstract

Background

Spirometry interpretation after lung transplantation (LTx) is complex, requiring a clear understanding of reference values and normal thresholds globally. Abnormal values are typically based on general population reference standards.

Methods

In April 2025, a 10-question online survey was conducted among International Society of Heart and Lung Transplantation-members to determine the reference values and normal thresholds used worldwide for post-transplant spirometry interpretation.

Results

Responses from 58 centers, covering 22,080 lung transplant recipients and representing ∼40% of global transplant activity, were analyzed. Most patients (63%) were followed in the United States or Canada. Global lung initiative (GLI) reference was used for 60%, with 47% using the race-neutral version. The lower limit of normal (LLN) was reported in only 19% of pulmonary function assessments. Regional differences were noted in obstruction definition and impairment grading.

Conclusions

While GLI-reference values are widely adopted, 40% of centers have yet to implement them, and LLN remains underutilized in spirometry reporting after LTx.