Although autopsy provides a definitive diagnosis, there is no single test to definitively diagnose Alzheimer’s disease in the living (Alzheimer’s Association 2012a; Uzun 2011). Alzheimer’s disease is diagnosed by exclusion in the living. In other words, physicians must confirm that neurological deficits are not being caused by other conditions (e.g., vascular dementia). The standard diagnostic strategy comprises collection of detailed patient history data, standardized assessment of cognition and functional status (e.g., mini-mental state examination), laboratory testing, and brain imaging examinations such as magnetic resonance imaging (MRI), positron emission tomography imaging (PET), and single-photon emission computed tomography (SPECT) (Biasutti 2012).
Discovering more specific biomarkers for Alzheimer’s disease may lead to the development of more accurate diagnostic tools for early diagnosis (Biasutti 2012). Some genetic biomarkers that raise the risk of Alzheimer’s disease have already been identified (Kasper 2004; Engelborghs 2012).