Race distorts blood test results for Alzheimer’s disease

According to a new study, three blood tests used to identify people in the early stages of Alzheimer’s disease work differently in blacks.

The fourth blood test, the Precivity AD test, is equally effective in detecting early-stage Alzheimer’s disease, regardless of the race of the person being tested, researchers say.

The cutoff between normal and abnormal test scores is usually set primarily on the basis of white volunteers, so in tests that perform differently in blacks compared to the white population, black patients There is an increased risk of misdiagnosis and inadequate medical care.

Most people are diagnosed with Alzheimer’s disease only after forgetfulness or confusion.like that Cognitive symptoms It occurs relatively late in the disease, more than 10 years after the brain first begins to change.

Scientists are working to identify people who have previously used it Blood test Detects Alzheimer-related proteins in the blood. It is also known as a biomarker. However, the field of biomarker research for Alzheimer’s disease is mostly based on data collected from groups of Caucasian participants, and there are concerns about whether such biomarker-based tests are equally effective in diverse populations. It’s happening.

“Unfortunately, as scientists have traditionally done in the study of Alzheimer’s disease, when using a limited research group and trying to apply the results to everyone, including people of diverse backgrounds, It can exacerbate health inequality, “says Associate Professor Susanne Schindler, a professor of neurology at the University of Washington in St. Louis. Neurology..

“I hope this paper will help explain the need to increase the diversity of participants in the Alzheimer’s disease study. My colleagues and I have more racial differences in blood biomarkers associated with Alzheimer’s disease. We are working on the development of a much larger multicenter collaborative study to better evaluate. This is a major priority for us. “

Researchers did not design the study to find out why some Alzheimer’s disease biomarkers give different results in whites and blacks, but the presence of other health conditions may play a role. ..

Blacks were more likely to have than whites in this study High blood pressure (67% vs 45%) and diabetes (28% vs 5%). Both conditions are associated with Alzheimer’s disease and may affect the performance of biomarker tests, researchers say.

The Precivity AD test uses high-resolution mass analysis to determine the ratio of the Alzheimer’s disease proteins amyloid beta 42 to amyloid beta 40, as well as the apolipoprotein E (APOE), a protein that affects the risk of Alzheimer’s disease. To measure.

Randall J. Bateman, a professor of neurology and co-author of the study, developed the underlying techniques behind the Precivity AD test. C2N, the manufacturer of Precivity AD tests, is a University of Washington start-up and based in St. Louis.

The researchers analyzed the accuracy of the Precivity AD test and blood test for the other two proteins.Neurofilament Light Protein Two forms of protein tau — 76 pairs of black and non-Hispanic white participants. To create a pair, researchers were drawn from a pool of volunteers participating in the study through Charles F. of the University of Washington and the Joan Knight Alzheimer’s Disease Research Center (Night ADRC), of age, gender, cognitive status, and APOE. High-risk genetic variation. Over 90% of individuals had no cognitive impairment.

Researchers used brain scans, cerebrospinal fluid surrounding the brain and spinal cord, or both to determine if each individual had Alzheimer’s disease brain changes. High levels of amyloid plaques found in brain scans or certain changes in cerebrospinal fluid are both considered evidence of the gold standard for Alzheimer’s disease.

Only the Precivity AD test accurately classified people by their Alzheimer’s disease status, regardless of their self-identified race. The other three blood tests were not very accurate in classifying people in the condition of Alzheimer’s disease. To make matters worse, they also performed differently in blacks compared to whites.

“Because Alzheimer’s disease is a global disease, the fact that these risk models have not been tested in many populations warns me,” said Assistant Professor of Psychiatry and Neurochemistry at Gothenburg University in Gothenburg. Says Thomas K. Crispy. ,Sweden.

“For example, APOE is a very good predictor of Alzheimer’s disease in Europeans, but it may not be a good predictor for non-European people. These risk models in different people. You need to study where it works, where it doesn’t, and what factors influence the performance of these models. “

“Racial standardization,” or tailoring tests individually for each race, is not a satisfactory solution to the problem of biomarker differences between race groups, says Sindler and Crispy. Such practices can create or exacerbate racial disparities.

For example, until 2021 NFL Racially-based cognitive tests, which are used on a daily basis, were used to assess ex-athletes for cognitive impairment associated with injuries in the field. Such tests consistently underestimated the degree of disability suffered by black players, making it difficult to obtain adequate compensation.

“It’s better to use tests that work equally well for all individuals, rather than trying to adjust race in some way,” says Sindler. “Alternatively, you can try to understand the underlying factors that make these obvious racial differences and adjust those underlying factors rather than race.

“What we don’t want to do is use these tests without assessing performance in different groups, because then we can’t meet our obligation to provide the best possible care for everyone. is.”

The National Institute on Aging and Cure Alzheimer’s Fund funded this work. C2N Diagnostics provided a plasma Aβ42 / Aβ40 assay for this study.

Bateman co-founded C2N Diagnostics, which developed the Precivity AD test. He worked with the University of Washington’s Technical Administration to file a patent application related to the test. Washington University and Bateman own shares in C2N Diagnostics and receive loyalty income based on the technology licensed by Washington University to C2N Diagnostics (stable isotope-labeled kinetics and plasma assays).

Source: Washington University in St. Louis