MAPT and Alzheimer disease: Working with plasma samples from a cohort of clinically diagnosed MCI and AD patients from our clinic and cognitively normal controls, > 30 candidate targets were screened including Aβ, oligomeric amyloid, fibrillar amyloid, various p‐tau isoforms, ubiquitin, alpha‐synuclein, and lysosomal‐associated membrane protein 1 (LAMP1).