AAIC 2026 Reveals Major Advances in Blood-Based Biomarker Tests to Improve Alzheimer’s Diagnostic Accuracy and Predict Cognitive Decline

Held annually, the Alzheimer’s Association International Conference (AAIC) is the premier international conference dedicated to advancing the science of Alzheimer’s disease and related dementias. This year’s conference was held in London, UK, bringing together more than 13,000 in-person and virtual attendees from 111 countries to share groundbreaking discoveries, exchange ideas, and foster collaboration across the field.

Among the groundbreaking research presented at this year’s conference were promising advances in blood-based biomarkers that could improve accuracy and accessibility of diagnostic testing for Alzheimer's disease and help identify symptom-free individuals at increased risk for future cognitive decline.

One study presented at AAIC 2026 included over 1,300 patients and 165 physicians from Sweden to examine whether incorporating a blood-based biomarker test into routine clinical care could improve physicians’ ability to diagnose Alzheimer’s disease. The blood test measures amyloid beta and phosphorylated tau, both of which are abnormal brain proteins linked to Alzheimer’s disease. The results showed substantial improvement in diagnostic accuracy in both primary care and specialty settings. Specifically, diagnostic accuracy before and after receiving blood test results improved from 65% to 93% and 74% to 89% among primary care physicians and dementia specialists, respectively. 

These findings are particularly significant because of the current challenges associated with diagnosing Alzheimer’s disease, which is a process often limited to specialist settings. While current diagnostic evaluations such as brain imaging and spinal fluid analysis provide immensely valuable information about the disease, they are often costly, invasive, or less accessible than a blood test.

As such, results of this study suggest that blood-based biomarkers could eventually help improve accuracy of Alzheimer's assessments in primary care, widely expanding access to timely diagnosis of the disease. However, researchers remain cautious about using these tests as a single diagnostic tool, as they are particularly helpful for ruling out the disease and should be interpreted alongside a comprehensive clinical evaluation. Dr. Judy Heidebrink, neurologist and clinical professor at the University of Michigan, emphasizes that when AD blood tests are used as a component alongside a comprehensive evaluation, they “improve diagnostic confidence and expedite the identification of persons most likely to benefit from the new Alzheimer’s disease treatments.”

Further, blood-based biomarkers may also provide information beyond diagnosis. A multicohort study based in North America, Japan, and Australia examined whether elevated levels of phosphorylated tau 217 (p-tau217) in the blood may help predict future cognitive decline among older adults who currently do not experience symptoms. 

Researchers found that having higher levels of p-tau217 were associated with future cognitive decline. Among symptom-free older adults with very high levels of the blood biomarker, researchers estimated a 78% risk of developing cognitive impairment within 10 years. Even those with moderately elevated levels had a lower but still significant risk of 15% over 5 years and 45% over 10.

These findings suggest that p-tau217 may eventually help researchers and clinicians identify individuals who may be at an increased risk for cognitive decline years before symptoms become apparent. While this provides immense potential to improve recruitment of appropriate participants for prevention trials and early interventions, researchers caution that p-tau217 is only one piece of the puzzle. Factors such as age, genetics, and other health characteristics may influence blood biomarker levels and individual risk, which points to the importance of additional research involving both larger and more diverse populations. However, blood-based biomarker testing is currently not clinically recommended for asymptomatic populations due to the predictive uncertainty of positive results and lack of proven disease-modifying treatments.

As advances in blood-based biomarkers continue to emerge, research centers like the Michigan Alzheimer’s Disease Research Center (Michigan ADRC) play an important role in evaluating these tools and determining how they can be applied across different populations and stages of the disease. Together, these findings presented at AAIC 2026 represent an important step toward making Alzheimer’s diagnosis more accurate and accessible while also improving our ability to identify individuals at risk for future cognitive decline. Although additional research and resources are needed before these tools can be widely incorporated into everyday clinical practice, their potential underscores our center’s mission of collaboration, research, and participation from individuals and families who continue to advance our understanding of Alzheimer’s disease and related dementias.

For more information on these studies, please visit:

https://aaic.alz.org/releases-2026/alzheimers-blood-test-accurate-diagnosis-pcp.asp 

https://aaic.alz.org/releases-2026/blood-test-p-tau217-predicts-alzheimers-risk.asp