As the performance of plasma p-tau231 was shown to be equivalent to plasma p-tau181 in several domains (e.g., distinguishing AD and non-AD and identifying Aβ positivity), and combining these biomarkers did not show significant improvement in their performance in the cases tested in this study—what does a measure of plasma p-tau231 offer compared to other plasma p-tau biomarkers that have been previously described? The gene discussed is MAPT; the disease is Alzheimer disease.