About the product
Elecsys Total-Tau CSF (Roche code CPS_000534) is an in vitro diagnostic test using the electrochemiluminescence immunoassay (ECLIA) method for the quantitative measurement of total tau protein in human cerebrospinal fluid (CSF).
According to Roche’s US product page, the test is used together with the Elecsys β-Amyloid (1-42) CSF assay to calculate the tTau/Abeta42 ratio in adults aged 55 and over being evaluated for Alzheimer’s disease or other causes of cognitive impairment. The description on Roche’s global page presents the test as an aid to other clinical evaluations in adults with cognitive impairment. Because the intended use may differ by region, the applicable definition should be confirmed from the relevant method sheet.
Measured parameter and clinical significance
The test measures the total tau (tTau) level in a CSF sample. According to the FDA 510(k) review document, if the tTau/Abeta42 ratio is below the cutoff, the result is consistent with a negative amyloid PET and lowers the likelihood that the patient’s cognitive impairment is due to Alzheimer’s disease. If the ratio is above the cutoff, the result is consistent with a positive amyloid PET.
According to the same document, a positive result does not establish a diagnosis of Alzheimer’s disease or another cognitive disorder, and the ratio is used as an aid to other clinical diagnostic evaluations. According to Roche, the performance of the test has not been established for predicting the development of dementia or other neurological conditions or for monitoring response to treatment.
Technical information
- Method: sandwich principle, electrochemiluminescence immunoassay (ECLIA); 2-point calibration
- Test time: 18 minutes (manufacturer's statement)
- Sample: human CSF
- Sample volume: 30 µL on the cobas e 801 and cobas e 402 modules; 50 µL on the cobas e 411 analyzer and the cobas e 601/602 modules (manufacturer's statement)
- Pack size: 100 tests (cobas e 402/801)
- Pack size: 60 tests (cobas e 411/601/602)
Use and compatibility
The Roche product pages list these systems:
- cobas e 402 and cobas e 801 modules
- cobas e 411 analyzer
- cobas e 601 and cobas e 602 modules
- MODULAR ANALYTICS E170 (on the US page)
System pages: cobas e 411 and cobas e 402. Other immunoassay reagents are on the hormone test kits and test kits pages.
According to Roche’s US page, the test is not designed to be used on its own and must be used together with the Elecsys β-Amyloid (1-42) CSF assay.
Frequently asked questions
Roche’s US page and the FDA document state that the test is to be used not on its own but together with the β-Amyloid (1-42) CSF assay to calculate the tTau/Abeta42 ratio. The definition on the global page differs and should be confirmed from the method sheet.
According to the FDA document, a positive result does not establish a diagnosis of Alzheimer’s disease or another cognitive disorder. The result is used as an aid to other clinical evaluations.
According to Roche, 30 µL of sample is used on the cobas e 801 and cobas e 402 modules, and 50 µL on the cobas e 411 analyzer and the cobas e 601/602 modules.
Contact
For product, quotation and technical information requests, use the contact form or write to info@tiliamedical.com.
