Evolving Landscape For Alzheimer's Blood Tests Gains Momentum Amid Inaccuracy Concerns

A new era in Alzheimer’s diagnosis is on the horizon as Dr. Suzanne Schindler and her team at Washington University School of Medicine pioneered blood tests capable of detecting sticky amyloid plaques, a key Alzheimer’s indicator. 

In 2019, Schindler and her team gained significant recognition for their publication, demonstrating that a blood test could detect amyloid plaques.

These tests, poised to replace expensive PET scans and uncomfortable spinal taps, offer a quick and less invasive way to identify patients and determine eligibility for emerging drugs targeting amyloid removal.

Though these new-generation blood tests are on the brink of transforming how doctors diagnose Alzheimer’s disease in patients experiencing memory loss, the accuracy of these blood tests remains a concern. 

Citing Dr. Schindler, NPR noted that the wide variability in test quality raises questions about reliability. 

Current blood tests for Alzheimer’s lack sufficient regulation, and as of now, none of them have received FDA approval.

In July 2023, Quest Diagnostics Inc DGX announced the availability of the AD-Detect Test for Alzheimer’s Disease on questhealth.com – the first blood test available for consumer purchase.

In October 2023, Laboratory Corporation Of America Holdings LH announced the launch and national availability of its ATN Profile, a blood-based test that combines three blood biomarkers to identify and assess biological changes associated with Alzheimer’s disease.

They are promoted as laboratory-developed tests, a distinct category typically subject to limited FDA supervision. 

In October, the FDA suggested a rule to enhance the scrutiny of such tests.

As the Alzheimer’s drug landscape evolves with recent FDA approvals like Biogen Inc BIIB / Eisai Limited ESALY Leqembi (lecanemab), which slows Alzheimer’s progression, the importance of accurate and timely diagnosis becomes paramount. 

A second Alzheimer’s drug, Aduhelm (aducanumab), received limited FDA approval in 2021, and a third, Eli Lilly And Co’s LLY donanemab, is likely to get full approval in the next few months.

In October 2023, The U.S. Centers for Medicare and Medicaid Services revised its policy permitting multiple uses of amyloid PET scans, a non-invasive brain scan crucial for identifying amyloid plaques.

“The one we developed can be 95% accurate”, says Dr. Randall Bateman, a professor of neurology at Washington University in St. Louis.

Blood tests offer a rapid means for doctors to identify individuals who may benefit from novel drugs targeting removing amyloid from the brain.

In January 2023, an NIH-funded research team developed a method named the soluble oligomer binding assay to identify toxic Aβ oligomers in patients’ blood.

By testing nearly 400 banked human blood plasma samples, they detected Alzheimer’s disease-promoting compounds, suggesting the potential for early diagnostic tests for Alzheimer’s and other neurodegenerative diseases.

Photo by Gerd Altmann via Pixabay