While the potential for co-morbidities to affect plasma biomarker concentrations has been a topic of considerable discussion in the context of clinical implementation of blood tests for AD, recent data suggest that the effect of what is generally considered the most impactful comorbidity—chronic kidney disease—may not be clinically meaningful for correct classification of amyloid status using plasma p-Tau 217 (39). Here, MAPT is linked to Alzheimer disease.