Roche announced that its Elecsys beta-Amyloid (1-42) CSF II (Abeta42) and Elecsys Total-Tau CSF assays (tTau) have received U.S. Food and Drug Administration (FDA) 510(k) clearance. The Elecsys AD CSF Abeta42 and tTau assays (used as a tTau/Abeta42 ratio) measure two biomarkers of Alzheimer’s pathology, beta-amyloid and tau proteins, in adults ages 55 and older being evaluated for the disease. 

Currently, the diagnosis of Alzheimer’s is largely one of exclusion (ruling out non-Alzheimer’s causes of symptoms) based on a number of evaluations, including various cognitive exams, routine laboratory tests and neuroimaging with a head MRI or CT scan. Obtaining an accurate diagnosis can take years,1 and one based on clinical criteria is reached only 70%-80% of the time.2 Additional evaluations with biomarkers specific to Alzheimer’s improve medical decisions, as they can identify underlying pathological changes early in the disease. 

Roche’s FDA-cleared Alzheimer’s tests in the U.S. include two ratios comprising three assays. Both ratios include Abeta42. The Elecsys beta-Amyloid (1-42) CSF II (Abeta42) and Elecsys Phospho-Tau (181P) CSF (pTau181) assays (used as a pTau181/Abeta42 ratio) that received FDA 510(k) clearance in 2022 and Elecsys beta-Amyloid (1-42) CSF II and Elecsys Total-Tau CSF assays (the tTau/Abeta42 ratio) are reective of the main Alzheimer’s pathologies and help clinicians more completely dene the disease biologically, facilitating a diagnosis of inclusion. 

“With the increasing likelihood of broad availability of new, Alzheimer’s disease–specific therapies, now is the time for healthcare professionals and institutions to prepare to meet the demand for diagnostic methods to streamline and accelerate the path to the right treatment, at the right time, for people with Alzheimer’s,” says Brad Moore, president and CEO of Roche Diagnostics North America. “An early and accurate diagnosis can help patients, caregivers and physicians determine a path forward, and the Elecsys CSF assays support diagnosis at early disease stages, when treatment is most effective.” 

Progression of Alzheimer’s occurs over a continuum with symptoms worsening over time. The Alzheimer’s Association estimates that, each day, more than 2,000 people ages 65 and older may transition from mild dementia due to Alzheimer’s to moderate dementia due to Alzheimer’s.

The appropriate use recommendations for new and emerging Alzheimer’s medicines call for conrmation of amyloid pathology.The only FDA-cleared methods to confirm amyloid pathology are CSF tests and PET scan imaging. 

The Elecsys AD CSF assays are concordant with amyloid PET scan imaging5 and have the potential to provide a more affordable and accessible routine option to conrm the presence of amyloid pathology in the brain. They also offer detection of both amyloid and tau biomarkers from one draw, with no radiation and potential to detect Alzheimer’s pathology in early stages of disease.6 The high cost, limited availability and patient exposure to radioactivity limit use and accessibility to PET. In addition, evaluating both amyloid and tau Alzheimer’s biomarkers using PET requires multiple appointments and procedures, and increases radiation exposure. 

The Elecsys pTau181/Abeta42 ratio is currently available. The new Elecsys tTau/Abeta42 ratio will be available in Q4 2023. Roche’s Elecsys AD CSF assays are already registered in 46 countries worldwide, including those accepting the CE mark. In July 2022, Roche also announced that the FDA granted Breakthrough Device Designation to its Elecsys Amyloid Plasma Panel, an innovative, minimally invasive and easily accessible solution that enables the measurement of Alzheimer’s biomarkers from a blood sample. These assays are still in development, but once they are available, they could be used to streamline patients toward conrmation of amyloid pathology using the Elecsys AD CSF assays. 

Featured Image: Roche’s Elecsys beta-Amyloid (1-42) CSF II (Abeta42) and Elecsys Total-Tau CSF assays (tTau) have received U.S. Food and Drug Administration (FDA) 510(k) clearance. The laboratories shown here is running one of the tests on a cobas e 601. Photo: Roche.


[1] van Vliet D, et. al, Time to diagnosis in young-onset dementia as compared with late-onset dementia. Psychol Med. 2013 Feb;43(2):423-32. doi: 10.1017/S0033291712001122. Epub 2012 May 28. PMID: 22640548.
[2] Sabbagh MN, Lue LF, Fayard D, Shi J. Increasing Precision of Clinical Diagnosis of Alzheimer’s Disease Using a Combined Algorithm Incorporating Clinical and Novel Biomarker Data. Neurol Ther. 2017 Jul;6(Suppl 1):83-95. doi: 10.1007/s40120-017-0069-5. 

[3] Alzheimer’s Association. 2022, December 19. Final and Formal Request for Reconsideration of National Coverage Determination (NCD) for Monoclonal Antibodies Directed Against Amyloid for the Treatment of Alzheimer’s Disease (CAG-00460N)., page 2, footnote 4. 

[4] Cummings, J., Apostolova, L., Rabinovici, G.D., et al. Lecanemab: Appropriate Use Recommendations. J Prev Alzheimers Dis (2023).
[5] Elecsys®β‐Amyloid (1‐42) CSF II assay, Elecsys® Phospho‐Tau (181P) CSF assay and Elecsys® Total-Tau CSF assay method sheets.
[6] Hampel H, et. al. Designing the next-generation clinical care pathway for Alzheimer’s disease. Nat Aging. 2022 Aug;2(8):692-703. doi: 10.1038/s43587-022-00269-x. Epub 2022 Aug 19. PMID: 37118137; PMCID: PMC10148953. [7] Elecsys®β-Amyloid (1‐42) CSF II assay and Elecsys® Total-Tau CSF assay method sheets.