FDA Clears Novel Alzheimer's Blood Test

The FDA recently approved the PrecivityAD2 blood test to assist in diagnosing Alzheimer's disease, according to C2N Diagnostics, which announced the clearance on Thursday. This innovative test measures plasma amyloid beta and tau peptide ratios to determine the risk of brain amyloid plaques, making it the first blood-based Alzheimer's biomarker for individuals as young as 40 experiencing cognitive symptoms.

Designed for use alongside clinical assessments in evaluating adults with signs or symptoms of cognitive impairment, PrecivityAD2 aids healthcare professionals in identifying patients with amyloid pathology, rather than serving as a standalone screening or diagnostic test. High-resolution mass spectrometry is employed to quantify Alzheimer's disease biomarkers in blood, resulting in an amyloid probability score 2 (APS2) that incorporates the ratio of phosphorylated tau 217 (p-tau217) to non-p-tau217, along with a plasma amyloid-beta 42/40 ratio to rule in or rule out Alzheimer's disease.

Clinical validation involving 1,142 individuals with cognitive decline signs or symptoms revealed PrecivityAD2 boasting a 97.6% positive predictive value (rule-in) and a 93.1% negative predictive value (rule-out), effectively detecting brain amyloid plaques. The test's diagnostic performance remained consistent across various patient demographics, including those with mild symptoms and advanced cognitive impairment, as well as those with comorbidities such as atrial fibrillation, autoimmune or inflammatory disease, chronic heart failure, kidney disease, coronary heart disease, depression, diabetes, dyslipidemia, cancer history, stroke or transient ischemic attack history, hypertension, or obesity.

A recent study from Sweden highlighted the test's utility in helping primary care physicians rule out Alzheimer's disease, while prior research demonstrated that the APS2 score outperformed primary care doctors or dementia specialists in detecting Alzheimer's among individuals with cognitive symptoms. In 2025, the FDA also approved two additional diagnostic blood tests for Alzheimer's disease: one for identifying Alzheimer's in symptomatic individuals and another for ruling out the disease in primary care settings.

Though lab-developed tests not cleared by the FDA are currently available on the market, the Alzheimer's Association released guidance in the previous year outlining sensitivity and specificity parameters for Alzheimer's blood tests to either identify or diagnose people with cognitive impairment. With an estimated 19 to 20 million U.S. adults aged 65 and older, as well as hundreds of thousands of individuals between 45 and 65, potentially benefiting from early diagnosis, PrecivityAD2 can be ordered by healthcare professionals experienced in evaluating cognitive impairment patients.

Currently, the test is available as a lab-developed product, with the FDA-cleared version expected to become available later this year.