Mielke MM, Frank RD, Dage JL, et al. - The findings of this investigation reveal that there are subtle differences between plasma p-tau species and platforms.

• This research involved data from the Mayo Clinic Study on Aging gathered from March 1, 2015, to September 30, 2017, and analyzed between December 15, 2020, and May 17, 2021.

• Of 200 involved candidates, 101 (50.5%) were male, and the median (interquartile range [IQR]) age was 79.5 (71.1-84.1) years.

• In total, 177 were cognitively unimpaired (CU) and 23 had mild cognitive impairment.

• The median (IQR) Simoa p-tau181 measure was 49% higher in amyloid-positive CU participants than in amyloid-negative CU participants, MSD p-tau181 measure was 53% higher, MSD p-tau217 measure was 77% higher, and Simoa p-tau231 measure was 49% higher.

• For the amyloid PET and tau PET metaregions of interest, there were no changes between the p-tau species.

• However, MSD p-tau181 and MSD p-tau217 reliably predicted aberrant entorhinal cortex tau PET in CU patients than Simoa p-tau181.

• Greater white matter hyperintensity volume and lower white matter microstructural integrity were linked to MSD p-tau181 and p-tau217, as well as Simoa p-tau181, but not p-tau231.