They used plasma samples from the first group of participants screened for AHEAD and used immunoprecipitation liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure phosphorylated and non-phosphorylated forms of tau181 and tau217 alongside Aβ42 and Aβ40 in order to further validate plasma p-tau species as early AD biomarkers. Here, MAPT is linked to Alzheimer disease.