The diagnosis of AD is confirmed post-mortem by histological examination of brain tissue. Pathologists look for the presence of amyloid plaques and neurofibrillary tangles using special staining techniques such as Bielschowsky silver staining, immunohistochemistry for amyloid-beta and tau proteins, and Congo red staining for amyloid plaques. The extent and distribution of these pathological features help differentiate AD from other neurodegenerative diseases.
