PrecivityAD2 is a blood test that helps doctors detect Alzheimer's-related amyloid buildup in the brain in symptomatic adults age 40 and older. People with mild cognitive impairment, which means early memory or thinking problems that stay noticeable but manageable, can compare it with other tests by weighing accuracy, uncertain results, age eligibility, and follow-up needs. The test supports a standard clinical workup and does not give a stand-alone diagnosis. It is also not meant for screening people without cognitive symptoms.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- What The Test Measures
- How Accurate Are The Results?
- Who Is Eligible?
- How To Compare Options With Your Clinician
What The Test Measures
C2N Diagnostics explains in the company clearance announcement that PrecivityAD2 uses high-resolution mass spectrometry to measure two blood ratios. Those ratios are amyloid-beta 42/40 and p-tau217 to non-phosphorylated tau217.
The test combines both ratios into an Amyloid Probability Score 2 from 0 to 100. A higher score means a higher likelihood of brain amyloid pathology.
How Accurate Are The Results?
NeurologyLive reported in its FDA clearance coverage results from a 1,142-person symptomatic validation group. Positive results matched amyloid PET or spinal-fluid testing 97.6% of the time, while negative results matched 93.1% of the time.
About 17.3% of results fell in an intermediate likely positive group with only 77.3% positive predictive value. A clear positive or negative still needs clinical context. An intermediate result especially needs clinician follow-up rather than action alone.
Who Is Eligible?
C2N Diagnostics states in the company clearance announcement that the clearance covers adults 40 and older with signs or symptoms of cognitive impairment undergoing evaluation. The test is an aid used with standard clinical workup, not a stand-alone diagnosis. It is not a screening test for people without symptoms.
People with mild cognitive impairment should bring a full symptom history and medication list to the visit. NeurologyLive notes the age-40 threshold reaches younger symptomatic patients than the two previously cleared blood assays. It describes PrecivityAD2 as a third FDA-cleared blood option in a category that had none before 2025.
How To Compare Options With Your Clinician
NeurologyLive reports performance stayed consistent across age groups and 12 comorbidities, including chronic kidney disease, atrial fibrillation, and diabetes. That consistency helps comparison, but other health issues and drugs can still affect care decisions. Bring these questions to compare blood testing with PET, spinal-fluid testing, or trial screening: Ask your clinician what an intermediate score would trigger for you before you order the test.
- What medicines and kidney, heart, or metabolic conditions should we review first?
- Would a positive, negative, or intermediate blood result change the plan for PET or spinal-fluid testing?
- What trial-evaluation referrals are available if amyloid pathology is likely?
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