Molecular and statistical weaknesses of the p-tau217/Aβ1−42 plasma ratio for alzheimer’s diagnosis

Abstract The FDA’s approval of the Lumipulse G p-tau217/Aβ 1−42 plasma ratio enhances access to Alzheimer’s diagnostics but risks confusing convenience with biological accuracy. The assay is scalable and non-invasive, yet it relies on a ratio of two markers that are unstable and only partly specific to the disease, raising concerns about reproducibility and interpretation. The reported performance is solid in carefully selected groups, but is likely to be less robust in broader real-world popula