Early diagnosis of Alzheimer’s disease is crucial to allow access to treatments that can help manage symptoms. Primary healthcare professionals play a vital role in recognizing patients’ individual risks, recommending lifestyle changes to prevent or slow disease progression, and, most importantly, facilitating timely diagnosis.
Alzheimer’s is the most common form of dementia, a general term for memory loss and other cognitive abilities that may seriously interfere with daily life.¹
The Roche Elecsys pTau181 is the only FDA-cleared blood test to rule-out Alzheimer’s associated amyloid pathology in the primary care setting.³
• pTau181 test measures phosphorylated Tau (pTau) 181 protein in human plasma, a key biomarker for Alzheimer’s pathology, including amyloid plaque and tau aggregate pathology.
• pTau181 test is intended for patients ages 55 and older who present with signs, symptoms, or complaints of cognitive decline.
Results from a multicenter study demonstrated that in an early disease-stage,
low-prevalence population, Elecsys pTau181 could rule out Alzheimer’s pathology with a 97.9% negative predictive value.³
Test Results:
A negative test result suggests a reduced likelihood that cognitive impairment is due to amyloid pathology; alternative causes should be considered. Interpret with clinical findings.
A positive test result is not diagnostic of Alzheimer’s disease and may not correlate with amyloid PET findings; further clinical evaluation is recommended. Interpret with clinical findings.
Limitations of Use:
- The Elecsys pTau181 test is not recommended for patients with signs, symptoms, or complaints of cognitive decline who are already referred to a specialist.
- Test performance has not been established for:
- Predicting development of dementia or other neurologic conditions
- Monitoring responses to therapies
Test Information
Test Code: TU65-8
Test Description: Phospho-Tau (181P)
Turnaround Time: 1 day*
Specimen Requirement: Primary Container: EDTA- Lavender Top (1.0mL); Alternate Container: ALQE- Aliquot Plasma (1.0mL) with a refrigerated stability of 7 days
*TAT is based upon receipt of the specimen at the laboratory.
References:
1. Center for Disease Control and Prevention https://www.cdc.gov/alzheimers-dementia/about/alzheimers.html Accessed 12.30.2025
2. Mattke S, Jun H, Chen E, Liu Y, Becker A, Wallick C. Expected and diagnosed rates of mild cognitive impairment and dementia in the U.S. Medicare population: observational analysis. Alzheimers Res Ther. 2023 Jul 22;15(1):128. doi: 10.1186/s13195-023-01272-z. PMID: 37481563; PMCID: PMC10362635.
3. Elecsys Phospho-Tau (181P) Plasma Product Information. www.accessdata.fda.gov Accessed 1.5.2026
