PrecivityAD2 Testing in 2026 is a blood test cleared to aid Alzheimer evaluation in adults 40 and older with cognitive symptoms, including mild cognitive impairment. Mild cognitive impairment means measurable memory or thinking change that does not block daily independence. In symptomatic patients it exceeded 90% accuracy against spinal fluid or amyloid PET scans, but it does not diagnose alone.
C2N Diagnostics reports that FDA cleared the test on Aug. 20, 2026 for symptomatic adults from age 40 the FDA clearance announcement. Results still need history, cognitive testing, exam, and clinical judgment.
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 does PrecivityAD2 measure?
- How accurate is it for symptomatic adults?
- When is the result unclear or less reliable?
- How do people with MCI access and use it?
What does PrecivityAD2 measure?
PrecivityAD2 measures two Alzheimer-related signals in blood plasma. It tests the amyloid-beta 42/40 ratio plus percent p-tau217 using mass spectrometry. The BrightFocus Foundation explains that the test combines them into the Amyloid Probability Score 2 for brain amyloid likelihood the BrightFocus test summary.
A higher score means brain amyloid buildup is more likely. A lower score means it is less likely. The score guides next steps, not treatment by itself.
How accurate is it for symptomatic adults?
A 2024 prospective JAMA study followed 1,213 patients with cognitive symptoms. In that group, APS2 exceeded 90% accuracy versus spinal fluid or amyloid PET and beat clinical evaluation without biomarkers, according to the C2N Diagnostics summary of the study the JAMA study summary. That result matters for mild cognitive impairment because early symptoms have many causes.
A high-accuracy aid helps doctors decide who needs referral, more testing, or close follow-up. It does not replace a full workup. The July 2025 Alzheimer's Association guideline sets tiers for blood tests. Tests with high sensitivity and specificity can triage, with positive results confirmed by PET or spinal fluid, while the highest tier may substitute for those tests.
When is the result unclear or less reliable?
About 1 in 6 patients gets an intermediate result, not a clear negative or positive. PharmaDeviceNews reports that 17.3% received an intermediate Likely Positive result with 77.3% positive predictive value, so added workup is needed the accuracy and intermediate-result report.
Families should plan for that outcome before testing. Severe kidney disease can also complicate reading. Mayo Clinic Laboratories notes that advanced chronic kidney disease can raise p-tau217, and plasma ratios reduce but do not remove that effect.
- Ask what an intermediate score would mean for you
- List kidney disease, dialysis, and recent hospitalizations
- Bring all memory test results and medication lists
- Ask whether PET or spinal fluid testing is advised next
How do people with MCI access and use it?
Only a clinician can order the test for MCI or dementia evaluation. The FDA-cleared kit is expected later in 2026, and until then the CLIA-validated laboratory version remains available.
Use the visit to link the score to your symptoms and function. Ask how the result changes the diagnosis, referrals, safety planning, or eligibility for other tests. Bring a care partner to record the plan and next appointments.
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