Skip to content

Medicine Matters

Sharing successes, challenges and daily happenings in the Department of Medicine

Medicine Matters Home Patient Care Changes to Pulmonary Function Test

Changes to Pulmonary Function Test

An update from the Johns Hopkins PFT Laboratories:

This week we had a software upgrade in the PFT Lab, which provided an opportunity to make some of the changes that we have been planning. We have adopted reference equations from the Global Lung Initiative (GLI) to create z-scores and percent predicted values. The GLI reference equations are based on global population data and are recommended in the most recent guidelines.1  The equations for spirometry do not include race or ethnicity, which is informed by evidence and the consistent with recent recommendations.2

You will see a new report format and the following statement at the bottom:

"As of March 30, 2023, the Global Lung Initiative reference equations are used in interpretation of spirometry, lung volumes and diffusing capacity. Race and ethnicity are not included as variables in the interpretation strategy. This may result in a change in the interpretation of results for patients tested at Johns Hopkins Pulmonary Function Laboratories."

This change may result in a shift in the percent predicted values. If you are assessing a patient over time, it is important to trend the absolute values of data, such as FEV1, FVC and DLCO, rather than the percent predicted. There may be some minor adjustments to the report format over the upcoming week so if you have any questions or note any anomalies, please contact us.

-Meredith McCormack and Bob Wise

  1. Stanojevic S, et al. ERS/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J. 2022 Jul 13;60(1):2101499. PMID: 34949706.
  2. Bhakta NR, et al. Race and Ethnicity in Pulmonary Function Test Interpretation: An Official American Thoracic Society Statement. Am J Respir Crit Care Med. 2023 Mar 27. PMID: 36973004.

Kelsey Bennett