A negative result, defined as pTau181/Abeta42 ratio value below cutoff 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.¹

Elecsys® AD CSF ratio achieves 90% concordance with amyloid PET^1,2

As depicted in the PET read classification graph, a pTau181/Abeta42 ratio result above the cutoff is consistent with a positive amyloid PET visual read.²

Elecsys® pTau181/Abeta42 ratio outperforms Abeta 42 as a standalone marker and achieves an area under the curve (AUC) of 96.3% (95.2%-98.0%) compared to single marker Abeta 92.1% (90.0%-94.3%) AUC.²

Abeta42, β-Amyloid (1-42); pTau181, Phospho-Tau (181P)

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