Roche has obtained FDA clearance for Alzheimer’s tests in the U.S. that include two ratios comprising three assays.
The Elecsys® beta-Amyloid (1-42)(Abeta42) protein , Elecsys® Phospho-Tau (181P) CSF , total-Tau CSF (tTau)can aid in the diagnosis of Alzheimer’s disease by measuring levels of beta-amyloid and tau protein.
The Abeta42 and pTau181 assays are currently available, while the total Tau and Abeta42 combination will be available in the fourth quarter of 2023. Roche’s fully automated Cobas immunoassay instruments are used for these assays
The build-up of amyloid beta and tau proteins is a hallmark of Alzheimer’s disease. These proteins form plaques and tangles in the brain, which damage nerve cells and lead to cognitive decline. The accumulation of amyloid beta and tau starts decades prior to symptom onset.
CSF biomarkers support early and accurate diagnosis of Mild Cognitive Impairment and Alzheimers Disease, as these biomarkers reflect the specific pathological accumulation of amyloid beta in plaques and tau in neurofibrillary tangles
Abeta42 proteins:
Elecsys beta-Amyloid (1-42) is a two step sandwich immunoassay developed by Roche Diagnostics. It is used to measure the levels of beta-amyloid 1-42 protein in cerebrospinal fluid (CSF).In Alzheimer’s disease, beta-amyloid aggregates to form plaques, which are one of the characteristic hallmarks of the disease. Elevated levels of beta-amyloid 1-42 in the CSF can be indicative of amyloid pathology associated with Alzheimer’s disease.
Studies have shown Elecsys AD CSF assays are concordant with amyloid PET scan imaging and can provide a more affordable, accessible routine method of confirming amyloid pathology through a single CSF draw.
The Elecsys® β-Amyloid (1-42) CSF II assay is not intended to be used as a stand-alone test and should only be used with the Elecsys® Phospho-Tau (181P) CSF or Elecsys® Total-Tau (tTau) assays to calculate the ratio of phosphorylated Tau (181P) (pTau181) to β-Amyloid (1-42) (Abeta42) (pTau181/Abeta42 ratio) or Total-Tau (tTau) to β-Amyloid (1-42) (Abeta42) (tTau/Abeta42 ratio).
| Sample Type | Sample Volume Required |
|---|---|
| Cerebrospinal Fluid | 30 µL – cobas e 801 module and cobas e 402 module 50 µL – cobas e 411 analyzer and cobas e 601/602 modules |
| Rejection criteria | Hemolytic CSF (Reddish) |
| Transportation requirements | sample should be kept at 2‐8 °C during transport and storage up to the time of measurement. Samples can be stored at 2‐8 °C for up to 14 days. If transport and storage at 2‐8 °C is not feasible, the sample can be transported/stored at room temperature (20‐25 °C). If this is the case, measurement is to be performed within 5 days |
Elecsys® Total-Tau CSF (tTau)
In vitro diagnostic Two-step sandwich immunoassay intended for the quantitative determination of the total tau protein concentration in human cerebrospinal fluid
Tau proteins are found in the central nervous system and play a role in stabilizing microtubules within neurons. However, in neurodegenerative diseases like Alzheimer’s, tau proteins become abnormal and accumulate as neurofibrillary tangles.
The measurement of Total-Tau (tTau) in cerebrospinal fluid (CSF) can provide insights into the extent of neurodegeneration and neuronal damage. Increased levels of tTau in CSF are associated with neuronal injury and can be indicative of neurodegenerative disorders.
The Elecsys Total-Tau CSF assay developed by Roche Diagnostics allows for the quantification of tTau levels in CSF. This assay, in combination with other biomarkers such as beta-amyloid (1-42), can help clinicians in evaluating individuals for Alzheimer’s disease and other neurodegenerative conditions.
| Sample Type | Sample Volume Required |
|---|---|
| Cerebrospinal Fluid | 30 µL – cobas e 801 module and cobas e 402 module 50 µL – cobas e 411 analyzer and cobas e 601/602 modules |
Elecsys® Phospho-Tau (181P) CSF (pTau)
Fibrillar deposits of highly phosphorylated tau are a key pathological feature of several neurodegenerative tauopathies including Alzheimer’s disease
Elecsys® Phospho-Tau (181P) CSF is an in vitro diagnostic Two-step sandwich immunoassay intended for the quantitative determination of the pTau 181 (Tau protein phosphorylated at threonine 181) concentration in human cerebrospinal fluid (CSF). Paired with the Elecsys® β-Amyloid (1-42) CSF II assay, the pTau181/Abeta42 ratio measures two main biomarkers of Alzheimer’s pathology, beta-amyloid 42 and phosphorylated tau 181 proteins, in adults ages 55 and older being evaluated for AD or other causes of cognitive impairment.
Using the ratio of phosphorylated tau to A beta 42 CSF level as a diagnostic test, sensitivity was 91.6%, specificity was 85.7%, and overall accuracy was 90.2% for predicting the presence of pathologic neuritic brain plaque.
| Sample Type | Sample Volume Required |
|---|---|
| Cerebrospinal Fluid | 30 µL – cobas e 801 module and cobas e 402 module 50 µL – cobas e 411 analyzer and cobas e 601/602 modules |