No. PrecivityAD2 is a blood test that can help detect Alzheimer's-associated brain amyloid, but its 2026 FDA clearance does not allow stand-alone diagnosis.
It must accompany an assessment by a professional experienced in evaluating cognitive impairment. A result can strengthen or weaken evidence that amyloid pathology is present. It cannot, by itself, establish that Alzheimer's explains a person's 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.
Official resources:
- Explore the official data from FDA — Use this primary source to review the underlying data.
- Check eligibility on Precivityad’s official study page — Use this page to check the study’s participation requirements.
Table of Contents
- What did the FDA clear?
- Who is the cleared test for?
- What does PrecivityAD2 measure?
- How strong were the reported results?
- What should a patient or caregiver do next?
What did the FDA clear?
The FDA database lists C2N Diagnostics' precivityad2 as a Class II device found "substantially equivalent" within the category of blood tests that assess amyloid pathology. The listing identifies the test as K253240, according to the FDA's device record. This clearance covers a test that aids an evaluation.
It does not turn the blood result into a complete Alzheimer's diagnosis or replace a clinician's judgment. The practical distinction is between detecting a biological feature and identifying the cause of cognitive problems. PrecivityAD2 addresses the first question; the wider evaluation addresses the second.
Who is the cleared test for?
The clearance applies to adults aged 40 or older who have signs or symptoms of cognitive impairment. They must already be undergoing evaluation for Alzheimer's disease or another form of cognitive decline.
C2N says the cleared indication explicitly excludes screening and stand-alone diagnosis in its announcement describing the intended use. That means the clearance does not cover testing asymptomatic people simply because they are curious or concerned about future risk. before treating the test as an option, check three points:.
- The person is at least 40.
- Signs or symptoms of cognitive impairment are present.
- A qualified professional is conducting a broader evaluation.
What does PrecivityAD2 measure?
PrecivityAD2 measures two ratios in blood: amyloid-beta 42/40 and phosphorylated-to-nonphosphorylated tau-217. Washington University School of Medicine says the test uses these measurements to estimate whether amyloid pathology is present in the brain. Amyloid pathology is associated with Alzheimer's, but it is not the entire clinical diagnosis.
A blood result does not independently establish why a person is having cognitive problems. The Alzheimer's Association explains that clinicians may also consider medical history, neurological and cognitive assessments, imaging, spinal-fluid testing, and other possible causes of impairment in its discussion of the clearance's clinical role. The appropriate combination depends on the individual evaluation.
How strong were the reported results?
C2N's validation study included 1,142 people with cognitive symptoms. Results were compared with amyloid-PET visual readings or spinal-fluid biomarkers. For results categorized as Positive, the reported positive predictive value was 97.6%.
For Negative results, the negative predictive value was 93.1%. A third category, Likely Positive, accounted for 17.3% of results and had a positive predictive value of 77.3%, according to C2N's validation figures. These percentages concern agreement with evidence of amyloid pathology in the symptomatic study group. They do not mean the test diagnosed Alzheimer's with 97.6% accuracy, and they should not be applied to screening people without symptoms.
What should a patient or caregiver do next?
Ask the evaluating professional what the result would add to the existing assessment. Also ask how each possible category—including Likely Positive—would affect decisions about imaging, spinal-fluid testing, or investigation of other causes.
Confirm which test version is being offered. As of August 20, 2026, C2N said the FDA-cleared version was not yet commercially available and was expected later in 2026, while its existing CLIA laboratory-developed test remained available.
