PrecivityAD2 is a blood test that helps memory clinics assess amyloid pathology alongside history, exams, and cognitive testing. A Positive score supports likely plaques and further workup, while a Negative score lowers plaque likelihood but leaves other causes open. The test is for adults age 40 and older with signs of cognitive impairment during an Alzheimer's evaluation, according to WashU Medicine in WashU Medicine. It does not screen healthy adults and does not replace 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 your APS2 number measure?
- What does a Positive result mean?
- What does a Negative result mean?
- Why is it adjunct-only?
- Which questions should you ask at results visit?
- Frequently Asked Questions
What does your APS2 number measure?
PrecivityAD2 uses high-resolution mass spectrometry to measure plasma Aβ42/40 and %p-tau217, then combines both ratios into an Amyloid Probability Score 2 from 0-100, as described by Patient Care Online in Patient Care. The first ratio reflects amyloid fragments in blood. The second reflects a tau form linked to amyloid buildup.
Your report shows Negative from 0-47 or Positive from 48-100. Negative aligns with a negative amyloid PET scan and low plaque likelihood. Positive aligns with a positive PET scan and high plaque likelihood.
What does a Positive result mean?
A Positive APS2 means plaques are likely and your team should pursue the next diagnostic step. In validation against PET or spinal fluid, Positive results had strong predictive value in the reported cohort. Ask whether imaging, spinal fluid testing, or referral is needed to confirm the cause.
A Positive result also shapes practical decisions about trials and treatment paths. For memory clinics, it supports further workup for diagnosis, trial eligibility, or anti-amyloid therapy confirmation, according to Medical News Today in Medical News Today. Bring medication lists, symptom timelines, and prior scans to that visit. Ask what confirmation your clinic requires before any therapy decision.
What does a Negative result mean?
A Negative APS2 means plaques are less likely and a PET scan would probably read negative. In the 1,142-person validation cohort, Negative results had 93.1% negative predictive value, according to NeurologyLive in NeurologyLive. That finding gives weight when symptoms point elsewhere.
It does not clear you of all brain disease. Other issues can impair memory, attention, sleep, mood, or blood flow. Ask what alternative causes fit your exam and what test comes next.
Why is it adjunct-only?
The clearance limits use to an aid alongside history, examination, and cognitive testing. It is not for asymptomatic screening, patients under 40, or repeated monitoring over time. Your clinic interprets the score only within that full picture.
Specialist guidance sets high bars for blood biomarkers in impaired patients. The Alzheimer's Association guideline distinguishes triage use from confirmatory use by sensitivity and specificity targets. Ask your specialist which role the test plays in your evaluation.
Which questions should you ask at results visit?
Use the visit to link the score to a plan. Ask how the result changes your diagnosis, referrals, or safety planning.
Ask what would trigger retesting or added imaging. Bring a family member to record the answers and next appointment date.
- Does my score fit Alzheimer's change or another cause?
- Do I need PET, spinal fluid, or neuropsychology next?
- Am I eligible for trials or therapy confirmation steps?
- What symptoms, medicines, or health issues could affect interpretation?
Frequently Asked Questions
Can I order PrecivityAD2 without cognitive symptoms?
No. It is cleared only for symptomatic adults 40 and older undergoing Alzheimer's evaluation with clinical exams.
Does a Positive score prove Alzheimer's dementia?
No. It supports amyloid pathology and further workup, while final diagnosis rests on clinical assessment and confirmatory steps.
Does a Negative score end the workup?
No. It lowers plaque likelihood but leaves other causes of impairment to evaluate.
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