For many Black Americans, the decision to donate a kidney to a loved one may come with a difficult question: what risks might they face years later after giving up an organ?
A new study led by researchers from University of California, San Francisco and Saint Louis University in Missouri suggests that a genetic test could provide a clearer answer.
The study, published Monday in JAMA Internal Medicine, followed 445 Black living kidney donors for nearly two decades. Researchers found that about 15 percent of them carried a high-risk version of the APOL1 genotype, a genetic variant that approximately doubled the likelihood of reduced kidney function later in life.
The findings add new evidence to discussions if Black Americans considering kidney donation should routinely receive APOL1 genetic testing, which remains unavailable at many transplant centers.
Currently, medical algorithms often classify Black kidney donor candidates as being at elevated risk. Yet the researchers found that the vast majority of Black donors in the study did not carry the high-risk genotype.
“With these data, it’s hard to defend not performing genotyping for all Black donor candidates, just as it would be hard to defend not measuring blood pressure,” according to a statement by the study’s corresponding author, Dr. Chi-yuan Hsu, who is Chief of the Division of Nephrology at UCSF Health.
“Since 85% of Black kidney donors do not have this genotype, genetic testing not only offers reassurance about outcomes, it could also increase the donor pool by not classifying all Black donor candidates as high risk, which frequently happens,” he added.
The live donor advantage
The majority of living kidney donations are made to a specific recipient, often a family member. Black patients account for roughly one-third of people waiting for kidney transplants, yet they make up only 8 percent to 14 percent of living donors. As a result, they are more likely to depend on kidneys from deceased donors, which generally do not function as long as organs from living donors.
The researchers said they tracked donors from the Scientific Registry of Transplant Recipients for an average of 18.5 years. Among donors with the high-risk APOL1 genotype, 14.7 percent experienced mild-to-moderate loss of kidney function, compared with 6.4 percent of donors without the genotype. Those with the high-risk variant were also more likely to show elevated levels of protein in their urine, a sign of kidney damage.
Still, the study found that severe outcomes remained uncommon. Three donors developed end-stage kidney disease during the study period, and only one of them carried the high-risk genotype.
The findings suggest that APOL1 testing may help move transplant medicine away from broad racial risk categories and toward more individualized assessments.
“Enabling APOL1 testing for all Black candidates means that risk assessment becomes individualized and supports a move toward precision medicine,” said co-senior author Dr. Meyeon Park, a Nephrology professor in the UCSF School of Medicine.
Yet according to a 2019 survey cited by the researchers, fewer than half of major transplant centers currently offer APOL1 testing to prospective Black donors.
The researchers emphasized that carrying the high-risk genotype should not automatically disqualify someone from donating a kidney.
Hsu said that having the high-risk APOL1 genotype should not necessarily rule out kidney donation, just as “kidney donors with hypertension or diabetes are acceptable if they are otherwise low risk.”
A level of reassurance
Co-senior author Dr. Krista Lentine, a professor of Saint Louis University, said the findings strengthen the case for broader access to genetic screening.
“APOL1 genetic testing adds another layer of information to the donor evaluation process, helping identify individuals who may be at higher risk while providing some reassurance for others considering living donation,” she said.
The researchers also presented separate findings suggesting that recipients of kidneys from donors with the high-risk genotype may face a greater risk of graft failure. Even so, those recipients may still have better survival prospects than patients who remain on dialysis.
For the researchers, the broader message is that a simple genetic test could help more people make informed decisions about one of the most personal gifts they can offer while potentially expanding the pool of donors available to patients waiting for a transplant.