Against essentialism in pulmonary function test interpretation

Pulmonary function test (PFT) interpretation involves the comparison of actual and predicted measures of pulmonary function. Current guidelines recommend that predicted pulmonary function be calculated with the use of Global Lung Function Initiative (GLI) equations, the parameters of which include age, sex, standing height, and race. Within populations of “normal” individuals (those without a history of tobacco use or respiratory symptoms), Black individuals have been found to have lower lung function than White individuals. These differences are reproduced in the GLI equations. Because separate equations are elaborated for each race, an FVC or FEV1 that is normal for a Black patient may be abnormal for a White patient, even when these patients share the same age, sex, and standing height.

The source of the observed difference in pulmonary function between Black and White individuals has important implications for the use of race in PFT interpretation. Race-specific equations have been motivated by the belief that race is a determinant of pulmonary function and by a desire to acknowledge differences while increasing precision and reducing overdiagnosis. However, these equations have been challenged on the grounds that differences in pulmonary function are the product of racism rather than race. Race-specific equations present these differences as normal, the product of biology rather than of racially mediated differences in prenatal care, early childhood nutrition, health care access, and air pollution exposure.