GFAP and Alzheimer disease: The UpSet plot for AD versus FTD shows that a combination of abnormal P‐tau181 and GFAP with normal NfL (39% with this result, 92% had AD) or abnormal P‐tau181 with normal GFAP and NfL (19% with this result, 89% AD) are highly indicative of AD, while having normal P‐tau181 but abnormal NfL combined with either normal GFAP (6% with this result, 100% FTD) or abnormal GFAP (4% with this result, 94% FTD) are highly indicative of FTD.