The FDA cleared C2N Diagnostics' PrecivityAD2 blood test on Aug. 20, 2026, for adults aged 40 and older with signs of cognitive impairment undergoing evaluation for Alzheimer's disease, according to the C2N Diagnostics announcement.
What changed is the age floor: it is the first FDA-cleared Alzheimer's blood test for symptomatic adults as young as 40, giving younger-onset families a sooner path to answers and care planning, as described in the Medical News Today report. PrecivityAD2 is a blood test that aids diagnosis by measuring Alzheimer's-related proteins and producing an amyloid score. For families, what comes next is practical: a single blood draw can replace an early referral for a PET scan or spinal tap, with clinical follow-up guiding treatment and planning decisions.
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:
- Read the original report from NIH — Use this primary source to review the complete report.
- Explore the official data from FDA — Use this primary source to review the underlying data.
Table of Contents
- What changed with this clearance?
- How does the test work?
- Why does age 40 matter for younger-onset families?
- What are the limits and what should you do next?
What changed with this clearance?
The clearance lowers the eligible age to 40 for people with symptoms. Earlier FDA-cleared blood tests from Fujirebio and Roche were cleared only for ages 55 and up. That left many symptomatic adults in their 40s without a cleared blood-test option.
Now a symptomatic adult aged 40 to 54 can receive the test during an Alzheimer's evaluation. The test is for people already showing cognitive impairment, not for routine checks. Evaluation by a qualified clinician remains part of the process.
How does the test work?
The FDA summary describes immunoprecipitation plus LC-MS/MS mass spectrometry to measure plasma proteins. The test quantifies Aβ42, Aβ40, and phosphorylated tau. It combines the Aβ42/40 ratio and percent p-tau217 into an Amyloid Probability Score, called APS2.
The score signals likely presence of brain amyloid pathology. An independent validation study published through the National Library of Medicine found about 91% accuracy versus amyloid PET at the prespecified cutoff, according to the independent validation study. Reported performance included about 90% sensitivity and 92% specificity, with positive predictive value near 93% and negative predictive value near 88%.
Why does age 40 matter for younger-onset families?
Younger-onset Alzheimer's can begin while people work, raise children, and manage mortgages. The Alzheimer's Association says extending clearance to age 40 recognizes that reality. More symptomatic 40-somethings can seek clarity instead of waiting years.
Earlier clarity helps families plan work leave, child care, finances, and support. It also helps clinicians sort Alzheimer's pathology from other causes of thinking problems. That distinction shapes referrals, monitoring, and treatment discussion.
What are the limits and what should you do next?
Practical Neurology notes the test is an aid to diagnosis, not screening or a stand-alone answer. It must be used with clinical assessment by professionals experienced in evaluating cognitive impairment.
A low or high score does not replace judgment, history, exams, and other testing. AJMC reports the practical gain is a less-invasive blood draw that can speed diagnosis when treatment works best. C2N said the FDA-cleared version was expected later in 2026, with its CLIA test available meanwhile.
- Seek evaluation if memory, language, judgment, or daily function declines.
- Ask a clinician experienced in cognitive impairment whether testing fits.
- Bring a family member, medication list, and timeline of changes.
- Discuss next steps for imaging, referrals, safety, work, and care planning.
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