Can a Blood Test Show I’ve Got Dementia?

Written by Active Minds on Wednesday the 23rd of May 2018.


If there is concern that you, or a loved one, is starting to show signs of dementia, then the first course of action you will need to take is a visit to your GP. Your GP will undertake a series of tests to determine mental abilities, such as memory and concentration. This is often called General Practitioner Assessment of Cognition (GPCOG).

Your GP will also order a series of blood tests. Whilst these blood tests do not diagnose dementia, they are used to eliminate any other conditions that may be causing symptoms similar to those of dementia. The blood tests will check:

  • Liver Function
  • Kidney Function
  • Thyroid Function
  • Haemoglobin A1c
  • Vitamin B12 and Folate Levels

A lack of Vitamin B12 in the blood can be a sign of a number of other conditions including pernicious anaemia. Symptoms include slowness, confusion and irritability, all common symptoms of dementia. Similarly, both underactive and overactive thyroids can cause dementia-like symptoms.


Whilst a blood test cannot diagnose dementia, there are certain tests that look for genetic markers that may signify a higher risk to developing the disease. Genetic blood tests will look for DNA abnormalities and mutations to identify these risks.

Most common gene mutations are:

  • PGRN – which may indicate a higher risk of developing frontotemporal dementia
  • APP, PS1 and PS2 – whose presence may indicate a higher chance of early-onset Alzheimer’s
  • APOE-e4 – a signifier of late onset Alzheimer’s

There is currently a considerable amount of research looking into the make-up of the blood of dementia patients. A number of types of dementia are caused by a build-up of abnormal proteins in the brain, and these proteins have been discovered to also be present in the blood platelets. This is a huge step forward in creating a blood test that can diagnose a person with dementia.

If you or a loved one has been diagnosed with dementia then engaging in dementia activities will help stimulate, encourage conversation and lift mood. All of our dementia products have been carefully researched and designed to help people with dementia lead positive, active lives.