Biomarkers.

Area of Science:

• Neurology
• Biomarker Discovery

Background:

• The Washington University Memory Diagnostic Center (MDC) evaluates approximately 4,000 patients annually for memory and cognitive concerns.
• The MDC utilizes blood biomarkers to assess for Alzheimer disease (AD) pathology and determine eligibility for anti-amyloid therapies.

Purpose of the Study:

• To evaluate the performance of the C2N Diagnostics PrecivityAD2 blood test in a clinical setting.
• To assess the concordance of the PrecivityAD2 test with established diagnostic methods like CSF analysis and amyloid PET scans.

Main Methods:

• The study included 143 patients with cognitive concerns who underwent the PrecivityAD2 blood test.
• The PrecivityAD2 test measures phosphorylated tau and Aβ42/Aβ40 ratios to generate an amyloid probability score 2 (APS2).
• A subset of 21 patients also underwent CSF or amyloid PET testing for comparison.

Main Results:

• 76% of the 143 patients tested positive by PrecivityAD2.
• In the subset of 21 patients, PrecivityAD2 showed 100% positive predictive value and 83% negative predictive value compared to CSF or PET.
• All 15 patients who were positive by PrecivityAD2 were also positive by CSF or PET.

Conclusions:

• The PrecivityAD2 blood test demonstrates high accuracy in identifying amyloid pathology.
• These findings support the use of accurate blood biomarker tests to guide the initiation of anti-amyloid treatments in patients with a high clinical likelihood of AD.