What is the typical diagnostic approach to Alzheimer's disease?

• A. Dx of exclusion with cognitive testing
• B. Definitive biomarker testing
• C. MRI findings confirm diagnosis
• D. Genetic testing alone

Answer: (A)

Diagnosing Alzheimer's disease is primarily a clinical process: you determine whether there is a progressive cognitive syndrome that fits dementia, and you rule out other possible causes of cognitive decline. Cognitive testing, along with a careful history and functional assessment, shows the pattern and trajectory of impairment typical for this condition—most often prominent memory loss with gradual decline in multiple cognitive domains.

There isn’t a single test that definitively confirms Alzheimer's in routine practice. Imaging and biomarkers can support the diagnosis but do not by themselves prove it. MRI or CT helps exclude other causes such as stroke, tumor, or hydrocephalus, while biomarker testing for amyloid or tau may reinforce confidence in uncertain cases or in research settings. Genetic testing is reserved for suspected familial early-onset cases or specific risk assessments, not as a general diagnostic tool for typical late-onset Alzheimer’s.

So the standard approach centers on diagnosing a progressive cognitive-communication and functional decline while systematically excluding other reversible or alternative causes.