Scatterplot of cerebrospinal fluid amyloid-β42 and phosphorylated tau values in the overall study population. Black dots represent non-ambiguous cerebrospinal fluid (CSF) results (non-Alzheimer’s disease (non-AD) in the upper left quadrant, AD in the lower right quadrant). Gray dots represent indeterminate CSF results. Cutoffs for amyloid-β42 (Aβ42) and phosphorylated tau (p-tau181) were calculated in the overall population. Among the 367 patients, 83 (23%) had indeterminate CSF results.