Blood Test Accurately Detects Brain Amyloid Pathology in Symptomatic Patients

C2N Diagnostics, LLC (St. Louis, MO, USA) is highlighting a peer-reviewed study that independently validates the performance of its PrecivityAD2 blood test among individuals with mild cognitive impairment or dementia. The PrecivityAD2 blood test combines plasma Aβ42/40 and %p-tau217 biomarkers into the Amyloid Probability Score (APS2) algorithm to aid in detecting the presence or absence of brain amyloid pathology in individuals with signs or symptoms of cognitive impairment undergoing evaluation for Alzheimer’s disease or other causes of cognitive decline.

The study, published in npj Dementia, reports that the test delivered 91% accuracy, 90% sensitivity, and 92% specificity when benchmarked against amyloid PET imaging—the gold-standard method clinicians traditionally rely on to confirm Alzheimer’s disease. These results were based on CLIA-established cutoffs and reinforce the test’s repeatable and robust performance. These findings also align with current expert recommendations, including the 2025 Alzheimer’s Association Clinical Practice Guidelines for confirmatory blood-based biomarkers that require ≥90% accuracy, sensitivity, and specificity.

Additional support for the test’s reliability comes from a large JAMA-published clinical study evaluating its use in primary care, where most patients first present with memory concerns. That study showed similarly strong performance, with the PrecivityAD2 algorithm, achieving accuracy above 90% compared to cerebrospinal fluid analysis or amyloid PET imaging, even in patients referred to memory specialists.

“The latest research adds to the growing body of literature that shows the PrecivityAD2 test effectively confirms Alzheimer’s disease pathology,” said C2N CEO and President Dr. Joel Braunstein. “This is more vital than ever as patients with mild cognitive impairment due to Alzheimer’s disease are very eager to access the new disease-modifying therapies, and scientists have stated these therapies are most successful when they start early.”

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