Neil Powe and Cynthia Delgado

Sometimes the best-intentioned efforts have unanticipated consequences. That’s the case with a test that doctors routinely use to measure how well a person’s kidney functions—one factor that helps determine their place on the kidney-transplant list. Back in 1998, an African-American researcher published a key finding that levels of a protein called creatinine tended to be higher in Black patients than in those who were white; higher creatinine levels overall were associated with poorer kidney function, but in Black patients, the higher levels didn’t necessarily correlate with worse function. A year later, researchers published the first formula for calculating a person’s eligibility for kidney transplants, and, using the creatinine finding, decided to factor in race as part of the criteria. Due to the way creatinine levels were included in the formula, many Black candidates were placed lower on the list simply because of their race.

In 2020, the National Kidney Foundation and the American Society of Nephrology formed a task force to re-evaluate the formula and determine if race should continue to be a factor. Dr. Cynthia Delgado, a nephrologist at the San Francisco VA Medical Center and the University of California, San Francisco, and Dr. Neil Powe, chief of medicine at Zuckerberg San Francisco General Hospital and a professor at the University of California, San Francisco, co-chaired the group and evaluated 23 options proposed by kidney experts. They decided on an algorithm that includes data from a more diverse population, so thresholds for measurements like creatinine are more of an average and not based solely on race.  

Last year, the United Network for Organ Sharing began using the revised formula to modify the wait times of Black patients already on the list. Other groups, including the U.S. Preventive Services Task Force, which evaluates and makes health-related recommendations, is reassessing screening for kidney disease with it in mind. The work is forcing “other organizations to re-evaluate race-based algorithms in medicine,” says Delgado.