PrecivityAD2 is a blood test that aids detection of amyloid plaques in adults age 40 and older with cognitive symptoms. For memory-clinic patients in their 40s to early 60s, its Amyloid Probability Score 2, a 0-100 score called APS2, is read as Negative from 0-47 or Positive from 48-100.
Younger-onset Alzheimer's means diagnosis before age 65. According to C2N Diagnostics, regulators cleared PrecivityAD2 on Aug. 20, 2026 for symptomatic adults age 40 and older, the first FDA-cleared Alzheimer blood test for patients that young C2N approval notice.
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 mean?
- How accurate is a Positive or Negative result?
- Who is this test for?
- What should you ask at your follow-up visit?
What does your APS2 number mean?
According to NeurologyLive, PrecivityAD2 uses mass spectrometry to measure plasma Aβ42/40 plus percent p-tau217, then combines them into APS2 test description. A higher score signals higher likelihood of brain amyloid.
Codex Genetics, a C2N distributor, lists 0-47 as Negative, consistent with a negative amyloid PET scan and low plaque likelihood cutoff guide. It lists 48-100 as Positive, consistent with a positive PET scan.
How accurate is a Positive or Negative result?
According to NeurologyLive, a 1,142-person symptomatic study compared the test with PET or spinal-fluid results validation summary. Overall positive predictive value was 97.6% and negative predictive value was 93.1%.
An intermediate likely-positive group made up 17.3% of cases and had 77.3% positive predictive value. A score near 47-48 therefore carries more doubt than a very low or very high score.
Who is this test for?
The test is for people with signs of cognitive impairment, not for routine screening without symptoms. It must be ordered by a professional experienced in cognitive impairment and used with standard exams and history.
That scope matters for younger adults. Symptoms in the 40s-50s have many possible causes, including sleep disorders, depression, thyroid disease, medication effects, and other neurologic conditions. A blood result alone does not diagnose Alzheimer's disease.
What should you ask at your follow-up visit?
Bring your exact APS2 number, current medications, sleep and mood changes, and family history. Ask how the result fits your exam, cognitive testing, and daily function. Symptomatic patients ages 40-64 can now get earlier amyloid triage in a memory clinic, but borderline scores still need clinical correlation and possible PET or spinal-fluid confirmation.
- Is my score clearly Negative or Positive, or near the cutoff?
- Do I need PET or spinal-fluid testing to confirm a borderline result?
- What other causes could explain my symptoms?
- What are the next steps for treatment planning, safety, work, and family support?
You Might Also Like
- Tauklarify Imaging for Alzheimer’s Tau Tangles in 2026: How Memory Clinic Patients Can Compare Testing Options
- How 2026 Tau Imaging News May Affect Alzheimer’s Workups: How Memory Clinic Patients Can Compare Testing Options
- Day-One Subcutaneous Leqembi for Early Alzheimer’s in 2026: How Adult Children Can Read the FDA Headline Carefully
