The Food and Drug Administration has cleared two new blood tests for Alzheimer’s disease, expanding options for diagnosing cognitive decline early. Roche’s Elecsys pTau217 test is authorized for adults aged 55 and older, while C2N Diagnostics’ PrecivityAD2 is cleared for symptomatic individuals as young as 40. These additions bring the total number of available Alzheimer’s blood tests to four.
Determining Dementia Types with Blood Tests
- Beyond Wastebasket Diagnoses: Blood tests measure specific biological proteins like phosphorylated tau and amyloid-beta to help clinicians determine exact types of dementia rather than relying on broad, imprecise labels.
- Not Stand-Alone Diagnostics: Regulatory agencies emphasize that these blood biomarkers must be interpreted alongside a patient’s medical history, physical symptoms, and other clinical findings.
- Targeted Access: Newer tests expand screening capabilities to younger populations, such as symptomatic adults aged 40 and older, though specialist counseling remains essential.
Closing the Diagnostic Gap at the Jersey City Psychiatry Conference
At the 2026 Jersey City Psychiatry Conference, George Grossberg, MD, the Henry and Amelia Nasrallah Professor in Geriatric Psychiatry at Saint Louis University School of Medicine, highlighted the persistent divide between dementia science and routine clinical practice. According to Grossberg, patients are frequently referred with ambiguous labels such as “dementia” or “senile dementia,” or their progressive symptoms are dismissed as normal age-related cognitive changes. This imprecision has historically delayed effective care and targeted interventions.
Grossberg credited the narrowing diagnostic gap to the arrival of three FDA-cleared blood-based biomarkers in a little over a year, with the first widely used assay cleared in May 2025. As clinicians learn to incorporate these diagnostics appropriately, experts anticipate a significant reduction in vague evaluations and a rise in precise etiological diagnoses. Identifying the underlying pathology allows physicians to match patients with disease-modifying therapies that prove most effective when administered during the early, mild stages of cognitive impairment.
Evaluating the Newly Cleared Biomarker Assays
The regulatory clearance of Roche’s Elecsys pTau217 test and C2N Diagnostics’ PrecivityAD2 marks a substantial shift in neurology. C2N Diagnostics’ PrecivityAD2 measures the amyloid-beta 42/40 ratio and the p-tau217/np-tau217 ratio, combining these values into an algorithm known as the amyloid probability score 2 (APS2).
Despite these high performance metrics, validation studies for younger cohorts remain relatively small. Clinicians are advised to exercise caution when applying performance estimates directly to individuals in their forties. A positive biomarker result in a younger adult carries profound implications for employment, family dynamics, financial planning, and emotional well-being, necessitating rigorous pre-test counseling and structured follow-up care.
| Test Name | Manufacturer | Biomarkers Measured | Age Indication |
|---|---|---|---|
| PrecivityAD2 | C2N Diagnostics | Amyloid-beta 42/40 ratio, p-tau217/np-tau217 ratio (APS2) | Symptomatic adults ages 40+ |
| Elecsys pTau217 | Roche | Phosphorylated tau 217 (pTau217) | Adults ages 55+ with signs of cognitive decline |
Fluid-Based Assays Versus Traditional Imaging
The broader landscape of neurodegenerative diagnostics continues to evolve away from purely invasive or cost-prohibitive procedures. Historically, confirming brain pathology required a lumbar puncture to extract cerebrospinal fluid or expensive positron emission tomography scans, which often range in price from $1,200 to $6,000 in the United States. Fluid-based biomarkers offer a less invasive and more accessible method to integrate biological data into clinical evaluations.
However, sample collection and assay sensitivity present historical bottlenecks in neurology. Specialized techniques are required because target analyte concentrations in bodily fluids are exceedingly low. Experts note that while blood tests streamline initial assessment, imaging and cerebrospinal fluid analyses remain crucial reference standards in complex or ambiguous clinical presentations.
Contraindications & When to Consult a Doctor
Blood-based Alzheimer’s biomarkers are strictly contraindicated as general population screening tools for asymptomatic individuals. These tests are indicated exclusively for adults experiencing documented signs or symptoms of cognitive impairment who are actively undergoing a formal diagnostic evaluation.
“Because a positive biomarker result at that age can have major implications for work, family, finances, and emotional well-being, careful patient selection, counseling, and a clearly defined follow-up plan are particularly important,” as noted during clinical evaluations of early-onset cohorts.
References
- Psychiatric Times. Coverage of the 2026 Jersey City Psychiatry Conference.
- MedicalNewsToday. FDA clears two new Alzheimer’s blood tests.
- Labiotech.eu. The new wave of biomarkers in Parkinson’s, Alzheimer’s & beyond.
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