Built-In Bias: How a Clinical Formula Delayed Kidney Transplants

For a long time, one of the most routine tools in kidney medicine contained a significant built-in error. It wasn't anyone's deliberate intention. But for Black patients with kidney disease, it quietly moved the goalposts by making it more difficult to obtain kidney transplants — and the cost was measured in years spent off the transplant waiting list. Every transplant center in the country was impacted, including OHSU in Oregon and UW Medicine in Washington.

The tool was the eGFR equation (the estimated glomerular filtration rate), a standard formula physicians use to assess how well a patient's kidneys are functioning. For decades, the equation included a race modifier that automatically gave higher scores for Black patients. A higher score means the kidneys appear to be working better, the patient appears less sick, and as a result they are less likely to be referred for a transplant evaluation or added to the waiting list. According to HRSA's explanation of the issue, the race variable in the most widely used eGFR formula had the potential to overestimate Black patients' kidney function by as much as 16 percent.

Glenda Roberts, a kidney disease patient and advocate, described what that looked like in practice in a report from the National Kidney Foundation. The old race-inclusive equation elevated her eGFR by 16%, which affected her ability to get on the transplant list by as much as two years. Not because her kidneys were healthier. Because a formula said they were. According to the National Kidney Foundation, Black patients on average wait a year longer than white patients to receive a kidney transplant, a gap that the eGFR error directly contributed to.

The correction came in stages. In 2022, the Organ Procurement and Transplantation Network (OPTN) unanimously prohibited the use of race-inclusive eGFR calculations for transplant purposes. As a result, in January 2023, all U.S. transplant programs, including those here in Oregon and Washington, were required to review their waiting lists and correct waiting times for Black candidates who had been disadvantaged. A related change followed in 2024, when OPTN officially removed the race variable from the Kidney Donor Risk Index, which shapes which donated kidneys are offered to which patients. According to the American Kidney Fund, more than 14,000 Black patients had their waitlist time shortened as a direct result of the policy change.

The eGFR story is one piece of a larger pattern. A significant gap exists between how many Black seniors likely have CKD and how many have been diagnosed. And research published through the National Institutes of Health found that awareness of chronic kidney disease among people with CKD risk factors is strikingly low overall, with racial minorities even less likely to be aware of their risks or their options, including transplantation. Low awareness leads to delayed diagnosis. Delayed diagnosis means delayed referral. And delayed referral means less time on the waiting list, which affects whether a transplant ever comes.

Researchers have begun using the phrase "structural competency" to describe what actually addressing these patterns requires, a recognition that health outcomes are shaped not just by individual biology, but by institutions, economic forces, and the policies that govern how care is delivered.

The eGFR fix was a structural correction that removed the race variable from the donor risk index. But structural competency means seeing the whole system: whether people in underserved communities across Oregon and Washington know they have kidney disease and whether they can access a nephrologist.

Those are all things policy can shape. And at the Northwest Kidney Council, shaping policy is what we're here to support. This National Donate Life Month, we're celebrating the extraordinary generosity of donors and the lives that transplants make possible.