According to Gram Research analysis, genetic variants common in African ancestry populations cause the standard kidney function test to show lower results by about 2 points, even though kidneys are working normally. These variants increase creatine production in the body, raising creatinine levels in blood and making the test appear worse than reality. The findings suggest doctors should use additional kidney tests before diagnosing kidney disease in African ancestry patients with low standard test results.
A new study from Gram Research analysis reveals that certain genetic variations common in African populations are making standard kidney function tests less accurate for people of African descent. Researchers found that a gene called GATM, which controls how the body makes creatine, is more active in people carrying African-enriched genetic variants. This causes higher levels of creatinine (a waste product) in the blood, making kidneys appear less healthy than they actually are on standard tests. The findings could help doctors better interpret kidney test results for millions of people and reduce misdiagnosis of kidney disease in African ancestry populations.
Key Statistics
A 2026 study of 6,587 people from Uganda, South Africa, and the United States found that African-enriched genetic variants in the GATM gene were present in approximately 50% of African ancestry individuals but rare in Europeans.
According to research reviewed by Gram, each copy of these GATM genetic variants was associated with approximately 2 ml/min per 1.73 m² lower kidney function test scores (eGFR) despite normal actual kidney function.
A 2026 analysis of African American veterans found that GATM variants increased the odds of chronic kidney disease diagnosis using standard tests by a measurable amount, but showed no association with actual kidney failure.
The GATM genetic variants explained 1.0%-1.7% of the variance in creatinine-based kidney function test results in the 2026 study, demonstrating a biomarker-specific effect independent of actual kidney function.
The Quick Take
- What they studied: Whether specific genetic differences common in African populations affect how accurately standard kidney tests measure kidney health
- Who participated: Over 6,500 people from Uganda and South Africa, plus African American participants from a large veteran health program
- Key finding: Genetic variants in the GATM gene, present in about half of African ancestry people, make standard kidney tests show lower kidney function scores by about 2 points, even though the kidneys are actually working fine
- What it means for you: If you have African ancestry and your kidney test results seem low, this genetic difference might explain it. Talk to your doctor about whether you need additional testing before accepting a kidney disease diagnosis based on standard tests alone.
The Research Details
Researchers studied DNA and health information from nearly 6,600 people in Uganda and South Africa to find genetic differences that affect kidney test results. They used advanced genetic analysis to identify which genes influenced creatinine levels—a waste product that doctors measure to estimate kidney function. They then looked at how these genes worked in the body and whether they actually affected real kidney function using a more accurate measurement called iohexol GFR.
The team also studied African American veterans to see if the same genetic patterns affected kidney disease diagnosis in the United States. This approach combined genetic data, blood tests, and actual kidney function measurements to understand exactly what was happening.
Standard kidney tests have been known to give misleading results for people of African descent, but doctors didn’t fully understand why. By identifying the specific genetic cause, this research explains part of the problem and could lead to better testing methods. Understanding these genetic differences helps prevent misdiagnosis and unnecessary treatment.
This study is strong because it used actual measured kidney function (iohexol GFR) rather than just estimates, included large populations from Africa and the United States, and confirmed findings across different groups. The researchers also checked whether the genetic variants affected other kidney markers, which helped prove the effect was real and specific to creatinine-based tests.
What the Results Show
The study identified genetic variants in the GATM gene that are common in African populations (found in about 50% of people) but rare or absent in European populations. These variants were associated with higher creatinine levels in the blood, which made kidney function appear worse on standard tests. Each copy of these genetic variants was linked to a drop of about 2 points on the standard kidney function score (eGFR), even though actual measured kidney function was normal.
Importantly, these genetic variants did NOT affect actual kidney function when measured more accurately. They also did NOT affect another kidney marker called cystatin C, proving that the effect was specific to how creatinine-based tests work. This means the variants influence creatinine production, not kidney health itself.
In African American participants, having these genetic variants increased the chances of being diagnosed with chronic kidney disease based on standard tests, but was NOT associated with actual kidney failure (end-stage kidney disease). This shows the variants cause test results to look worse than reality.
The research revealed that these genetic variants increase the activity of the GATM gene, which controls creatine production in the body. Higher creatine production leads to more creatinine in the blood. The variants explained about 1-1.7% of the differences in creatinine-based kidney test results across the populations studied. The effect was independent of age, sex, body composition, and actual kidney function, meaning it’s a pure genetic effect on the test itself.
Previous research has shown that African ancestry populations have systematically lower kidney function test scores compared to European ancestry populations, even when kidney health is similar. This study provides the first clear genetic explanation for part of this difference. It builds on earlier work showing that creatinine-based tests are less accurate for African ancestry people and supports the need for better testing methods.
The study focused on one specific genetic location (GATM) and likely explains only part of the kidney test differences seen in African ancestry populations. The research was conducted primarily in Uganda and South Africa, so results may not apply equally to all African ancestry groups worldwide. The study didn’t test whether adjusting kidney test calculations for these genetic variants would improve accuracy in clinical practice. Additionally, the variants explained only 1-1.7% of total variation in test results, meaning other factors also contribute to test differences.
The Bottom Line
For people of African ancestry with low kidney function test results, doctors should consider additional testing (such as cystatin C-based tests or measured GFR) before diagnosing chronic kidney disease. Healthcare providers should be aware that standard kidney tests may underestimate actual kidney function in African ancestry populations due to genetic factors. This is a strong recommendation based on clear evidence of test bias.
People of African descent who have been told they have low kidney function should discuss these findings with their doctor. Healthcare providers caring for African ancestry patients should understand this genetic explanation for test differences. Public health officials and kidney disease organizations should consider updating kidney disease screening guidelines to account for these genetic differences.
These genetic effects on kidney test results are present from birth and don’t change over time. However, recognizing this bias could immediately change how doctors interpret test results. If additional testing is needed, results would typically be available within days to weeks.
Frequently Asked Questions
Why do African ancestry people get different kidney test results?
Genetic variants common in African populations increase creatine production, raising blood creatinine levels and making standard kidney tests appear worse. A 2026 study found these variants affect about 50% of African ancestry people but are rare in Europeans, explaining part of the test differences.
Does this genetic difference mean I actually have kidney disease?
Not necessarily. The 2026 research shows these genetic variants affect the test result itself, not actual kidney function. People with these variants had normal measured kidney function despite low standard test scores, suggesting the test may be misleading without additional testing.
What should I do if I have low kidney function test results and African ancestry?
Ask your doctor about additional kidney tests like cystatin C or measured GFR before accepting a kidney disease diagnosis. The 2026 study suggests standard tests alone may not accurately reflect your actual kidney health if you carry these common African ancestry genetic variants.
Can this genetic difference be treated or fixed?
The genetic variants themselves don’t need treatment because they don’t harm kidney function. Instead, doctors should interpret standard kidney tests differently for people with African ancestry, using additional tests to confirm actual kidney health rather than relying on creatinine-based estimates alone.
How common are these kidney test-affecting genetic variants?
A 2026 study found these GATM variants in approximately 50% of African ancestry populations, making them very common. However, they’re rare or absent in European ancestry populations, which explains why kidney test interpretation differs between racial groups.
Want to Apply This Research?
- Track your kidney function test results (eGFR scores) over time and note your ancestry background. If you have African ancestry, record whether your doctor mentions genetic factors when interpreting your results.
- If you have African ancestry and low kidney function test scores, use the app to schedule a conversation with your doctor about getting additional kidney function tests (like cystatin C) before accepting a chronic kidney disease diagnosis.
- Set quarterly reminders to review your kidney function test results and compare them to previous years. Note any changes in your actual kidney health symptoms (swelling, fatigue, changes in urination) separately from test score changes to help distinguish real kidney problems from test bias.
This research identifies genetic factors affecting kidney function test interpretation and does not constitute medical advice. If you have been diagnosed with kidney disease or have concerns about your kidney health, consult with your healthcare provider or nephrologist (kidney specialist). Do not change any kidney disease treatment or monitoring based on this information alone. This study suggests additional testing may be appropriate for African ancestry individuals with low standard kidney function test results, but only your doctor can determine what testing is right for you based on your complete health picture.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.