PrecivityAD2 is a blood test cleared in 2026 to help identify brain amyloid pathology in symptomatic adults age 40 and older. For primary-care patients with cognitive symptoms, it brings younger-onset evaluation into the regular clinic visit. Amyloid pathology means abnormal amyloid protein buildup in the brain linked to Alzheimer's disease. Younger-onset Alzheimer's affects people under age 65, a group that includes people in their 40s and 50s, according to the Alzheimer's Association.
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
- Who can use the test now?
- How does the blood test work?
- What changes in a primary-care visit?
- What are the limits and next steps?
Who can use the test now?
C2N Diagnostics announced on Aug. 20, 2026 that FDA cleared PrecivityAD2 for adults age 40 and older with signs or symptoms of cognitive impairment, in the company announcement. That clearance makes it the first cleared Alzheimer's blood test for that young age. That age cutoff matters for younger-onset patients.
Earlier cleared blood tests covered only older symptomatic adults, with Fujirebio Lumipulse and Roche Elecsys pTau181 labeled for ages 55 and older, according to Clinical Lab, in the lab testing review. The age-40 clearance newly brings younger patients into labeled use. Use remains tied to symptoms and clinical judgment. AJMC reporting on C2N and FDA labeling states the test is cleared only as an aid alongside standard workup by clinicians experienced in cognitive evaluation, not for screening healthy people or as a stand-alone diagnosis.
How does the blood test work?
The FDA decision summary describes immunoprecipitation plus LC-MS/MS measurement of plasma A-beta 42, A-beta 40, p-tau217 and non-phosphorylated tau217, in the FDA decision summary. The test combines the A-beta 42/40 and p-tau217 ratios into an Amyloid Probability Score 2 from 0 to 100. A blood draw is less invasive than lumbar puncture or PET imaging.
WashU Medicine states that a single draw can accelerate amyloid assessment, earlier care planning, and timely treatment decisions when treatments work best. A higher score signals higher likelihood of brain amyloid pathology. A lower score signals lower likelihood, but neither result alone establishes Alzheimer's disease.
What changes in a primary-care visit?
Primary-care doctors can order the test during evaluation of memory, thinking, or functional symptoms. The result sits beside history, exam, cognitive testing, and medical review, not in place of them. Accuracy in primary care looked close to specialty care in recent research.
Medscape reported that primary-care physicians using PrecivityAD2 reached 93 percent diagnostic accuracy versus 94 percent for dementia specialists and changed planned management in over 60 percent of cases in a prospective study of more than 1,300 patients presented at AAIC 2026, in the AAIC meeting report. Practical gains include fewer early referrals for invasive testing and faster next steps. Patients can discuss work planning, safety, support needs, and treatment timing sooner when amyloid information arrives earlier.
What are the limits and next steps?
False positives and false negatives occur. The BrightFocus Foundation states that symptoms from stress, other neurologic causes, or mixed pathology still require history, exam, cognitive testing, and sometimes spinal-fluid or PET confirmation.
Ask your clinic about these practical checks: Bring a family member or close contact who sees daily function. Concrete examples of missed appointments, work errors, driving concerns, medication mistakes, or language changes help the clinician interpret the score.
- Do I have documented signs of cognitive impairment that fit the labeled use
- What other causes have been ruled out through exam and testing
- Will a result change referrals, imaging, care planning, or treatment timing
- What follow-up test is planned if the blood result and clinical picture disagree
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