The Future of Blood-Based Biomarkers in Alzheimer Disease

The evolution of Alzheimer disease biomarkers has dramatically changed when and how clinicians can identify underlying pathology. What was once confirmed primarily through postmortem examination can now be assessed using cerebrospinal fluid, amyloid PET imaging, and increasingly, blood-based assays, raising the possibility of detecting disease much earlier in its biological course.

At the 2026 Alzheimer's Association International Conference (AAIC), investigators presented an analysis evaluating P-tau217 blood-based assays for identifying amyloid pathology in cognitively unimpaired individuals. Across 2 independent cohorts, including the Bio-Hermes study and pooled Lilly cohorts, P-tau217 demonstrated strong rule-in performance and was evaluated for noninferiority against amyloid PET quantitation. The findings provided further evidence for the potential use of blood biomarkers to identify underlying Alzheimer pathology before cognitive impairment becomes apparent.

In this concluding episode of the NeurologyLive^® Special Report, Yogesh Shah, MD, MPH, FAAFP, medical director of the Broadlawns Memory Clinic, site principal investigator for the University of Iowa Geriatric Workforce Empowerment Program, and board member of the Iowa Chapter of the Alzheimer's Association, reflects on the broader evolution of biomarker testing. Shah discusses how blood-based approaches compare with established methods and why more accessible testing could help shift Alzheimer care toward earlier detection, risk reduction, and eventually prevention.

Transcript edited for clarity.

Yogesh Shah, MD, MPH, FAAFP: Biomarker is a general term that we've used in medicine for a long time. When you go to your clinic for a checkup or physical, we measure things like your blood pressure and sometimes obtain blood tests. Those are all markers of health, or biomarkers.

For Alzheimer disease and dementia, biomarkers in the past were mainly identified at autopsy after death. If a person donated their brain for study and we found plaques or tangles, then postmortem we could determine that the person had Alzheimer disease.

Then, about 15 years ago, we began using lumbar puncture to evaluate these biomarkers. Through cerebrospinal fluid, we can measure proteins such as amyloid and tau that are associated with the disease. Then came amyloid PET scans, which allowed us to evaluate amyloid pathology in living patients, and now we have blood tests.

So, the use of biomarkers in diagnosing Alzheimer disease is evolving very quickly and becoming increasingly meaningful in day-to-day practice. With that will come earlier diagnosis and, hopefully, better quality of life for patients.

Today, when people are diagnosed with dementia late, they may live with dementia for 10 or 12 years or longer, often unable to fully enjoy their lives or make their own decisions. If we can detect the disease earlier, people may have more opportunities to work on their lifestyle and reduce their risk.

I compare this with heart disease. Forty years ago, people died from heart attacks without realizing that heart disease could be predicted and prevented. In the late 1950s and 1960s, the Framingham Heart Study showed us that heart attacks could be predicted and prevented by identifying factors such as uncontrolled blood pressure, high cholesterol, obesity, diabetes, smoking, and physical inactivity.

Out of that, preventive cardiology became a major field in the 1970s and 1980s, and it changed the trajectory of heart disease. I'm hoping, and many others in the field are hoping, that something similar will happen with Alzheimer disease. We'll be able to better predict who may develop the disease and then gradually move toward prevention, allowing people to live longer with a better quality of life.

This conference coverage information is produced independently by Neurology Live and supported by Eli Lilly and Company who has no direct influence on the content itself.