Alzheimer's Blood Biomarker Tracks Brain Amyloid Across Racial Groups

Blood Test Tracks Brain Amyloid Consistently Across Diverse Populations

A blood test measuring phosphorylated tau 217 (%p-tau217) tracks elevated brain amyloid across diverse racial groups with consistent accuracy. Researchers analyzed screening data from 15,612 cognitively unimpaired adults ages 55 to 80. The Journal of the American Medical Association (JAMA) Neurology published the results.

Testing took place at 106 research sites globally. Participants provided blood samples before undergoing confirmatory positron emission tomography (PET) scans. In each racial group, higher %p-tau217 readings matched higher levels of amyloid buildup on PET scans.

Baseline Biomarker Levels Differed Across Racial and Ethnic Groups

Baseline blood biomarker levels varied between demographic groups even though the test tracked brain amyloid in all cohorts. Asian and Black participants showed lower average biomarker levels than white participants. Hispanic participants also had lower levels than non-Hispanic participants.

These differences raise biological questions. Prior observational research indicates that Black and Hispanic groups face a higher overall rate of dementia. Dementia risk involves multiple pathways beyond the amyloid changes captured by this blood test or a PET scan.

Genetic Risk Factor APOE ε4 Relates to Higher Biomarker Levels

Individuals carrying the apolipoprotein E (APOE) ε4 variant have higher blood levels of %p-tau217 than non-carriers. The APOE ε4 variant is an established genetic risk factor for Alzheimer's disease. This pattern appeared across every racial and ethnic group in the study.

The strength of the relationship varied between populations. Carrying the gene led to variable biomarker increases across groups. Studying diverse cohorts helps researchers clarify how genetics shape biomarker presentation.

How Blood Screening Fits Into Preclinical Alzheimer's Clinical Trials

Blood biomarkers serve as an initial filter to select participants for brain imaging in clinical trials. Participants were undergoing screening for the AHEAD 3-45 trials testing the drug lecanemab. The drug clears amyloid accumulation from the brain.

Current trials test whether treating cognitively unimpaired individuals with elevated amyloid can delay cognitive decline. Using %p-tau217 to pre-screen candidates reduces the need for expensive PET imaging. This approach makes trial recruitment more accessible for historically underrepresented communities.

Practical Next Steps for Adults Tracking Cognitive and Metabolic Health

Blood biomarker tests for Alzheimer's disease remain clinical screening tools rather than standalone diagnostic products. They require clinical interpretation alongside imaging. Standardized reference ranges for diverse populations are still being defined.

Adults tracking metabolic and cognitive health should review any memory concerns with a primary physician. Ask your doctor about current Alzheimer's clinical trial registries or available diagnostic pathways in your region.