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For years, physicians and medical students, many of them Black, have warned that the most widely used kidney test — the results of which are based on race — is racist and dangerously inaccurate. Their appeals are gaining new traction, with a wave of petitions and papers calling renewed attention to the issue.

In recent weeks, physicians and medical students at a handful of prominent universities have called on their administrations to end the use of race-based kidney testing, pointing to such changes at Beth Israel Deaconess Medical Center in 2017 and at Mass General Brigham and the University of Washington earlier this summer.


On the heels of those petitions, as well as a widely circulated New England Journal of Medicine analysis of the kidney test and other medical tools that are biased against Black patients, the National Kidney Foundation and the American Society of Nephrology announced this month that they will convene a task force to evaluate the use of race in kidney testing.

“[Science] has been a conspirator of racism since the genesis of racism. And it is our duty as physicians to be keenly aware and critical of that history, and how we still operate within it despite our best intentions,” said Paloma Orozco Scott, a medical student who co-authored a petition to Mount Sinai calling to end the use of race as a factor in the test.

The test — which measures what’s known as estimated glomerular filtration rate, or eGFR — has historically considered four factors: age, gender, race, and levels of creatinine — the waste that kidneys filter out of blood. But the race of a patient can only be bucketed into two groups: Black, or not Black. That’s based on a flawed assumption that dates back to the formula’s creation, when medical experts presumed that Black people have higher muscle mass on average, leading to higher kidney function.


Normal adult kidneys function around or above a score of 90, while patients can be added to the kidney transplant waitlist once they hit 20 or below. Patients who are Black automatically have points added to their score, which can make results appear more normal than they might be — which in turn, could delay needed treatment.

“When science comes out with a statement that really aligns with what people believe — in this case, oh, of course Black people are different — no one questions it,” said Vanessa Grubbs, an associate professor of nephrology at University of California, San Francisco, and co-author of one petition. “This equation assumes that Black people are a homogeneous group of people, and doesn’t take into account, how Black is Black enough?”

Grubbs and others in the field have advocated for years to move away entirely from using muscle mass as a consideration, instead arguing that the test should only take age, gender, and creatinine levels into account.

“There’s been a lot of conversation around how this New England Journal of Medicine article has seemed to be part of this tipping point, when folks like myself have been talking and writing about this issue for well over a decade,” said Grubbs. “It’s just an example of who is listened to, and who is taken seriously in this country.”

A handful of schools and health systems have changed their eGFR testing protocols in recent years, a few having done away with the adjustment for muscle mass entirely. UCSF and Zuckerberg San Francisco General Hospital last year opted to start adjusting for muscle mass, instead of race — but physicians have petitioned the school to do away with that adjustment as well, arguing it is not scientifically founded.

The issue has also gained the attention of medical students like Naomi Nkinsi, now a rising third-year student at the University of Washington School of Medicine.

One of five Black students in her class of around 100 at the school’s Seattle location, Nkinsi said she was used to speaking up in class about racism by the time they were learning about the kidney, in the winter of her first year of school. The lecture ended with a brief explanation of eGFR testing, including how race was factored into the results.

“I knew that racism played a role in medicine and how people interact with patients, but I didn’t realize how ingrained it was in the actual algorithms,” Nkinsi said. “And that’s my body that they’re talking about. That’s my mom and dad, those are my siblings.”

Nkinsi said that after she spoke up in class about the inherent racism in the eGFR tests, she followed up with her professors. School leaders planned more lectures and discussions on treatment disparities, and the school’s Anti-Racism Action Committee started talking about it and planning town halls. Then in May of this year, the school officially made the change.

Scott and her classmate Carina Seah, rising second-year students at the Icahn School of Medicine at Mount Sinai, decided to petition the school in June, after a lecture on how math can be racist in medical algorithms like the eGFR tests, by Staci Leisman, an associate professor in nephrology.

“Because we see science is such a rigorous process, and because we see these equations as such objective measures, it’s really hard to imagine that they would be influenced by racism,” Seah said.

Leisman has given that particular lecture — inspired by a student who challenged the formula as racist during class — for the past five or six years and always receives a spirited response, she said. But this was the first year a student, spurred by her lecture, took steps to change how eGFR results are calculated.

While many physicians and students are excited to see the building momentum, they also believe there are even more pressing, systemic issues of medical racism that need to be addressed.

“I think there’s a lot of frenzy over institutions trying to rid themselves of racism, as if it is something that you can policy out, that you can legislate out, but in fact it is something that lives within us as individuals in the system,” said Scott.

It’s unclear how widespread the changes will be, and whether national organizations will take on the cause. The National Kidney Foundation declined to comment on eGFR testing. The press release announcing its task force acknowledges that race is a social construct and not a biological one, but makes no definitive statements on changing the test, only on examining it.

“I would be surprised if medicine across the board made substantive changes,” said Grubbs. But she is encouraged seeing the next generation of doctors speak up on this issue.

“I’m sure I don’t even know all the different places where medical students in particular are really kicking up dust around, [saying,] ‘You all are teaching us to be racist. We came here to learn how to be competent caring, doctors.’”

  • The whole concept of eGFR should be revisited. Of the four parameters only creatinine is a measured quantity, specific to that individual. The other three are attempts at population level averages. On average, males are likely to have more muscle mass than females and muscle mass does declines with age, but for any individual, these population averages may not be relevant. Rather than racist, these are lazy surrogates overall. I can recall my mother who always displayed a severely impaired eGFR while she was still able to walk on her own into her 90’s. My assumption was that she was clearly an outlier relative to her age cohort in terms of muscle mass.

    Rather than focus on simply removing a single ‘racist’ component, efforts should be directed to identifying a better estimate of muscle mass in an individual without relying on population averages. Everyone would be better served by a more accurate method to determine GFR.

  • Just a question, if with more muscle mass (fibers) than more energy is used. If that is true then wouldn’t a correlation of more waste produced be true as well. With that the wouldn’t the kidney be affected. Now is the function of the kidney just biochemical metrics?

    However, with the assumption that Africans have a higher muscle mass is racist and ignores variability of base function of the kidney of Africans with genetic variation.

  • People are “seeing” racism everywhere. That’s not helpful in identifying actual racism. I see no evidence that the test is racist. (A test cannot be racist; the intent of its creators and users may be.) If what is said here is correct (and Cian Lang gives reason to doubt it) then the test is inaccurate due to incorrect assumptions. The same is true of the continued use of the BMI. (In the BMI’s case, it fails to allow for differences in muscle mass.)

  • There is very little content in this article that contributes to an understanding of exactly why race was ever used as a factor in calculating GFR. The convenient assumption made is that physicians and scientists are racist. A much more detailed and nuanced version can be found here, followed by a critical finding:

    “Regardless of the mechanism underlying higher serum creatinine, both the MDRD and CKD-EPI studies demonstrated a higher measured GFR in black persons for a given serum creatinine. This is hard to ignore.”

    This article focuses on the angle that an artificially high GFR measurement can delay needed treatment, and ignores the fact that an artificially low GFR measurement can accelerate unnecessary treatment. Dialysis and immunosuppressive medication for transplants are not blessings.

    Perhaps we should acknowledge that creatinine levels are not an ideal surrogate for GFR and search for a better one rather than hysterically attempting to wallpaper over biological differences between human populations in the name of antiracism?

    • I agree there should be efforts made to find a better surrogate measure for GFR, but I don’t see anything “hysterical” about the movement to eliminate one aspect of the current measure that, to my understanding, has been shown to be inaccurate and based on inadequate science. No one in this context is trying to deny biological differences between populations but I can’t see how a doctor’s subjective decision that someone is African-American (based on what, skin color? name? SES?) can ever be a good enough proxy for that individual’s genetic and environmental influences on muscle mass let alone creatine-GFR relationship.

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