further specialist investigations if Alzheimer's disease suspected
Last edited 05/2022
If the diagnosis is uncertain and Alzheimer's disease is suspected, consider either:
- FDG-PET (fluorodeoxyglucose-positron emission tomography-CT), or perfusion SPECT (single-photon emission CT) if FDG-PET is unavailable or
- examining cerebrospinal fluid for:
- either total tau or total tau and phosphorylated-tau 181 and
- either amyloid beta 1-42 or amyloid beta 1-42 and amyloid beta 1-40
- If a diagnosis cannot be made after one of these tests, consider using the other one.
- the older a person is, the more likely they are to get a false positive with CSF fluid exam
- do not rule out Alzheimer's disease based solely on the results of CT or MRI scans.
- do not use apolipoprotein E genotyping or electroencephalography to diagnose AD
- be aware that young-onset Alzheimer's disease has a genetic cause in some people.