Scientists develop blood test for Alzheimer’s disease

Scientists say test could replace a costly brain scan or painful lumbar puncture and enable earlier detection of disease

Scientists have developed a blood test to diagnose Alzheimer’s disease without the need for expensive brain imaging or a painful lumbar puncture, where a sample of cerebrospinal fluid (CSF) is drawn from the lower back. If validated, the test could enable faster diagnosis of the disease, meaning therapies could be initiated earlier.

Alzheimer’s is the most common form of dementia, but diagnosis remains challenging – particularly during the earlier stages of the disease.

Current guidelines recommend detection of three distinct markers: abnormal accumulations of amyloid and tau proteins, as well as neurodegeneration – the slow and progressive loss of neuronal cells in specified regions of the brain. This can be done through a combination of brain imaging and CSF analysis. However, a lumbar puncture can be painful and people may experience headaches or back pain after the procedure, while brain imaging is expensive and takes a long time to schedule.

Prof Thomas Karikari at the University of Pittsburgh, in Pennsylvania, US, who was involved in the study, said: “A lot of patients, even in the US, don’t have access to MRI and PET scanners. Accessibility is a major issue.”

The development of a reliable blood test would be an important step forwards. “A blood test is cheaper, safer and easier to administer, and it can improve clinical confidence in diagnosing Alzheimer’s and selecting participants for clinical trial and disease monitoring,” Karikari said.

Although current blood tests can accurately detect abnormalities in amyloid and tau proteins, detecting markers of nerve cell damage that are specific to the brain has been harder. Karikari and his colleagues around the world focused on developing an antibody-based blood test that would detect a particular form of tau protein called brain-derived tau, which is specific to Alzheimer’s disease.

They tested it in 600 patients at various stages of Alzheimer’s and found that levels of the protein correlated well with levels of tau in the CSF, and could reliably distinguish Alzheimer’s from other neurodegenerative diseases. Protein levels also closely corresponded with the severity of amyloid plaques and tau tangles in brain tissue from people who had died with Alzheimer’s. The research was published in the journal Brain.

The next step will be to validate the test in a broader range of patients, including those from varied racial and ethnic backgrounds, and those suffering from different stages of memory loss or other potential dementia symptoms.

Karikari also hopes that monitoring levels of brain-derived tau in the blood could improve the design of clinical trials for Alzheimer’s treatments.

Contributor

Linda Geddes Science correspondent

The GuardianTramp

Related Content

Article image
Hopes raised for early blood test to help fight Alzheimer’s disease
Studies measuring levels of the protein tau in blood offer hope of developing treatments

Sarah Boseley Health editor

28, Jul, 2020 @10:19 PM

Article image
Alzheimer’s blood test could predict onset up to 20 years in advance
US researchers say blood test can be 94% effective in spotting those at risk of the disease

Kevin Rawlinson

02, Aug, 2019 @8:18 AM

Article image
Long naps may be early sign of Alzheimer’s disease, study shows
Excessive daytime napping likely to be symptom rather than cause of mental decline, say scientists

Hannah Devlin Science corespondent

17, Mar, 2022 @3:37 PM

Article image
Alzheimer’s study finds 42 more genes linked to higher risk of disease
Evidence linking Alzheimer’s to disruption in the brain’s immune system is hailed as ‘enormous clue’

Hannah Devlin Science correspondent

04, Apr, 2022 @3:00 PM

Article image
Strobe lighting provides a flicker of hope in the fight against Alzheimer’s
Exposure to flashing lights stimulates brain’s immune cells to clean up toxic proteins causing the disease, study finds

Hannah Devlin Science correspondent

07, Dec, 2016 @6:00 PM

Article image
Alzheimer's study reveals new genes implicated in disease

Largest study yet into genetics of Alzheimer's disease identifies double the previous number of genes associated with disorder

Ian Sample, science correspondent

27, Oct, 2013 @6:05 PM

Article image
Could Down's syndrome point the way to preventing Alzheimer's disease?

People with Down's are dramatically more prone to Alzheimer's than other adults. Now, scientists have united in a bid to pin down why – and to find drugs that could halt dementia. Robin McKie reports

Robin McKie

13, Oct, 2012 @11:04 PM

Article image
Viagra could be used to treat Alzheimer’s disease, study finds
US scientists say users of sildenafil – the generic name for Viagra – are 69% less likely to develop the form of dementia than non-users

Andrew Gregory Health editor

06, Dec, 2021 @7:32 PM

Delaying retirement could prevent early dementia, say scientists

Keeping the brain active later in life could reduce chances of an early onset of Alzheimer's disease, according to research

James Meikle

18, May, 2009 @10:01 AM

Article image
Focus on lifestyle factors to prevent Alzheimer’s disease | Letters
Letter: Prof A David Smith highlights an effective approach to the disease

28, Nov, 2022 @5:39 PM