# K221842: Elecsys B-Amyloid (1-42) CSF II, Elecsys Phospho-Tau (181P) CSF

- Pathway: 510(k) (Traditional)
- Applicant: Roche Diagnostics
- Decided: Dec 7, 2022 after 166 days
- Product code: QSE (Alzheimer’S Disease Pathology Assessment Test)
- Device class: 2
- Regulation: 21 CFR 866.5840
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 1 generation back to DEN200072 (2022). 1 ancestor in all.
2 later devices descend from it; 2 cite it directly.
0 of 4 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- DEN200072: Lumipulse G ß-Amyloid Ratio (1-42/1-40), Fujirebio Diagnostics,Inc. (2022) Summary page 4.

## Most influential descendants
- K252163: Elecsys Phospho-Tau (181P) Plasma (2025), 0 descendants of its own
- K231348: Elecsys ß-Amyloid (1-42) CSF II, Elecsys Total-Tau CSF (2023), 0 descendants of its own

## Indications for use
Elecsys β-Amyloid (1-42) CSF II and Elecsys Phospho-Tau (181P) CSF are in vitro electrochemiluminescence immunoassays for the measurement of the β-Amyloid (1-42) (Abeta42) and Phospho-Tau (181P) (pTau181) protein concentrations in cerebrospinal fluid (CSF) from adult patients aged 55 years and older being evaluated for Alzheimer's disease (AD) and other causes of cognitive impairment to generate a pTau181/Abeta42 ratio value. A negative result, defined as pTau181/Abeta42 ratio value below cut-off or an Abeta42 value above the measuring range, is consistent with a negative amyloid positron emission tomography (PET) scan result. A negative result reduces the likelihood that a patient’s cognitive impairment is due to AD. A positive result, defined as pTau181/Abeta42 ratio value above cut-off, is consistent with a positive amyloid PET scan result. A positive result does not establish a diagnosis of AD or other cognitive disorder. The pTau181/Abeta42 ratio result is used as an adjunct to other clinical diagnostic evaluations. Limitations of Use The performance of the pTau181/Abeta42 ratio has not been established for: ▪ Predicting development of dementia or other neurologic conditions ▪ Monitoring responses to therapies

Source page: https://510kreport.com/device/K221842
Methodology: https://510kreport.com/methodology