PrecivityAD2 is a blood test that helps doctors assess Alzheimer's brain changes in adults who already have thinking or memory symptoms. Memory clinic patients avoid overreading the headline by treating it as an aid to a full exam, not proof of Alzheimer's or future dementia. The test measures two blood ratios linked to amyloid and tau, then combines them into an Amyloid Probability Score 2 from 0 to 100. A doctor experienced in memory disorders must interpret that score with cognitive testing, history, and other workup results.
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 the APS2 score tell you?
- Who is eligible for the test?
- Why does a positive still need confirmation?
- How can you avoid overreading your result?
What does the APS2 score tell you?
PrecivityAD2 uses high-resolution mass spectrometry to measure plasma A-beta 42/40 and a phosphorylated tau ratio. The lab blends both ratios into one score that estimates the likelihood of amyloid pathology. According to Patient Care Online, in a 1,142-person study of people with symptoms, a clear positive score matched amyloid PET or spinal fluid results 97.6% of the time and a clear negative matched 93.1% of the time detailed clearance report.
Those numbers apply only when symptoms are already documented and the sample is compared against accepted brain biomarkers. That same report notes 17.3% of participants fell in an intermediate likely-positive band with only 77.3% predictive value. An intermediate result is far less certain and needs careful follow-up rather than a firm answer.
Who is eligible for the test?
NeurologyLive reports the FDA cleared PrecivityAD2 on Aug. 19, 2026 for adults age 40 and older with signs of cognitive impairment being evaluated for Alzheimer's or other decline clearance coverage. It was the first cleared Alzheimer's blood test available down to age 40 for symptomatic patients.
ADRAG, summarizing FDA records, states the cleared use is only as an adjunct to clinical assessment by professionals experienced in cognitive impairment summary of FDA records. It is explicitly not a screening test for healthy people and not a stand-alone diagnosis. A memory clinic should therefore document impairment before ordering the test. A request based on worry alone, family history, or a desire to predict future dementia falls outside the clearance.
Why does a positive still need confirmation?
A blood signal is not the same as a clinical diagnosis. Other causes of memory loss, mixed brain changes, and test limits can shift what a score means for one person. The Alzheimer's Association guideline for specialty care says tests with at least 90% sensitivity and 75% specificity may triage, where a negative helps rule out pathology but a positive needs PET or spinal fluid confirmation guideline announcement.
Only tests reaching at least 90% sensitivity and 90% specificity may substitute for those confirmatory tests. For families, the practical point is simple. A negative APS2 carries more weight for ruling out Alzheimer's pathology than a positive carries for ruling it in without further testing.
How can you avoid overreading your result?
Treat the headline as a starting question, not an answer. Ask how your score fits imaging, lab work, medications, sleep, mood, and other medical causes of cognitive change.
Bring a list of symptoms, onset dates, and daily-life examples to the follow-up visit. Ask your clinic team to write down what your APS2 category means and what test comes next.
- Confirm impairment was documented before the blood draw.
- Ask which APS2 category you received: negative, intermediate, or clear positive.
- Ask whether guidelines call for PET or spinal fluid confirmation in your case.
- Do not use the result to screen relatives without symptoms or to forecast future dementia.
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