The assay uses a small sample of blood to measure different phosphorylated and nonphosphorylated forms of the tau protein, including those at the tau217 and tau181 sites. The assay builds on research demonstrating that interactions among abnormal tau and beta-amyloid proteins, as well as several other factors, play a role in Alzheimer's-related brain changes.

Researchers can now evaluate and characterize p-tau MAA's ability to identify Alzheimer's pathology at the early stages of Alzheimer's disease, C2N said.