Elecsys^® Total -Tau CSF

Robust and accurate biomarker tests to aid clinical decisions

Robust and accurate biomarker tests to address unmet needs in Alzheimer’s disease

Elecsys® Total-Tau CSF (tTau) is an in vitro diagnostic immunoassay intended for the quantitative determination of the total tau (the 6 human brain Tau isoforms) protein concentration in human cerebrospinal fluid (CSF). Paired with the Elecsys® β-Amyloid (1-42) CSF assay, the tTau/Abeta42 ratio measures two biomarkers of Alzheimer’s pathology, beta-amyloid 42 and tau proteins, in adults ages 55 and older being evaluated for AD or other causes of cognitive impairment.¹

Studies have shown that while CSF β‑Amyloid (1‑42) levels decrease to around half the level in controls, CSF tTau levels increase around 2‑3 fold in mild-moderate AD patients compared to age‑matched controls.^2,3

The Elecsys® Total-Tau CSF assay is not intended to be used as a stand-alone test and should only be used with the Elecsys® β-Amyloid (1-42) CSF assay to calculate the ratio of Total-Tau (tTau) to β-Amyloid (1-42) (Abeta42) in CSF (tTau/Abeta42 ratio).¹

A negative result, defined as tTau/Abeta42 ratio value below cutoff is consistent with a negative amyloid positron emission tomography (PET) scan result and reduces the likelihood that a patient’s cognitive impairment is due to AD. A positive result, defined as tTau/Abeta42 ratio value above cut off, is consistent with a positive amyloid PET scan result.¹

Although a positive result does not establish a diagnosis of AD or other cognitive disorders, the use of tTau/Abeta42 ratio in addition to other clinical diagnostic evaluations enhances diagnosis accuracy and can streamline patient management.^1,4,5

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References

Total-Tau (tTau) CSF method sheet 2023-04.
Mattsson N, Zetterberg H, Hansson O, et al. CSF biomarkers and incipient Alzheimer disease in patients with mild cognitive impairment. JAMA. 2009;302(4):385-393.
Hampel H, Blennow K. CSF tau and β-amyloid as biomarkers for mild cognitive impairment. Dialogues Clin Neurosci. 2004;6(4):379-90.
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;6(Suppl 1):83-95.
Hansson, O. et al. (2018). CSF biomarkers of Alzheimer’s disease concord with amyloid-β PET and predict clinical progression: A study of fully automated immunoassays in BioFINDER and ADNI cohorts. Alzheimers Dement 14(11), 1470-1481.