A narrow intermediate zone means fewer inconclusive results. This supports clearer clinical decision-making and helps limit additional CSF or amyloid PET testing to the smaller group of patients who still require further clarification.

Plasma pTau181 can offer a useful negative predictive value, but an elevated pTau181 is not indicative of amyloid pathology². pTau217 reflects amyloid burden more closely and supports a dual-cutoff read-out that works in both directions: reliable rule-out and rule-in.

ApoE ε4 status determination is mandatory prior to anti-amyloid treatment. Homozygous carriers have a markedly higher risk of ARIA (amyloid-related imaging abnormalities), which is clinically relevant for treatment decisions.

Combined with pTau217, ApoE ε4 further improves discrimination to an AUC of 0.970 (from 0.939; p = 0.02)⁵ in a memory-clinic cohort.

A positive result indicates a high likelihood of amyloid pathology. It should be interpreted together with the patient’s clinical assessment, cognitive testing, neuroimaging and clinical history, and may support further specialist evaluation or confirmatory testing where appropriate.

A positive result does not by itself establish a diagnosis of Alzheimer’s disease.

For patients ≥ 55 years with signs, symptoms or complaints of cognitive decline associated with Alzheimer’s disease.

Elecsys® pTau217 is the first blood test for Alzheimer’s disease pathology with a single-assay design – offering accuracy comparable to spinal-fluid testing via one routine blood draw, and turning a diagnostic pathway that today takes 3.5 years on average into a quick, actionable result¹.

It works as a first-line triage tool: in the clinical practice cohort, plasma pTau217 showed high concordance with amyloid PET (AUC0.933), with fewer than 6%of results in the indeterminate zone needing confirmatory CSF or PET testing.