Recommended tests

 

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.

 

 

Routine use of amyloid PET in the diagnosis of dementia or mild cognitive impairment is not recommended.

 

 

Amyloid PET may be considered for improving the diagnosis of Alzheimer’s dementia in situations where there is still uncertainty following specialist assessment and structural brain imaging, for example in those with an atypical presentations or young-onset dementia.

 

 

Any consideration of amyloid PET should follow a full clinical assessment by a dementia specialist, and discussion of the potential risks from radiation.

 

 

Testing of established CSF biomarkers should be arranged by dementia specialists following clinical assessment. The risks and benefits of undertaking a lumbar puncture should be discussed with the individual, and any risks managed.