Today, it takes years to get an Alzheimer's diagnosis in the UK. The NHS just launched a £5 million project to develop rapid tests to spot the disease in a single drop of blood.
Today in the United Kingdom, people who are concerned they may be showing the early signs of Alzheimer’s disease or another form of dementia often wait as long as four years for an appointment with a neurological specialist, testing, and a diagnosis, according to reporting from The Guardian. So, it’s a source of hope for advocates across the UK that scientists there are gearing up to trial simple blood tests for Alzheimer’s, with the aim to make diagnosis faster, more accurate and more accessible.
A National Health Service research team has announced a £5 million, five-year sprint, backed by Alzheimer’s Research UK and the Alzheimer’s Society, to pilot new blood-based diagnostics, which experts say could give NHS providers the ability to diagnose the disease within seconds. Several of these blood tests are in development across the biopharma industry, some are being used in clinical trials, and in the U.S. and Hong Kong, a small number of such tests are already available in private clinics. But they’re very much still in the experimental phase.
“Nearly four in 10 people in the UK who have dementia have not received a diagnosis,” Fiona Carragher at the Alzheimer’s Society expressed said. “We also know that those who do have a diagnosis have often waited many months, sometimes years, to receive it. This means thousands of families are stuck in limbo, trying to manage symptoms and plan for the future without access to the vital care and support that a diagnosis can bring.”
Dr. Susan Kohlhaas, the executive director of research and partnerships at Alzheimer’s Research UK, underscored the need for scalable, accurate, and non-invasive tests like these blood-based diagnostics, stressing the necessity of significant investment to move these tests out of the lab and into real-world settings.
“We expect more people to be coming forward for diagnosis, we expect them to be coming forward at a younger age and we expect them to be coming forward with less obvious symptoms,” she told The Guardian. “We need better, more scalable tests that are also accurate and compare to current gold-standard methods.”
Existing diagnostic methods are falling short
Back in 2021, the NHS explored another route to faster, more accessible Alzheimer’s diagnosis: an AI-based integrative cognitive assessment (ICA) app, designed by a company called Cognetivity to detect signs of cognitive impairment by yet another new means — pictures of animals on a digital tablet. At the time, the ICA was still awaiting approval from the Food and Drug Administration, but the approach was promising enough to have secured European regulatory approval as a medical device, and the NHS leapt to deploy it in both primary and specialist clinical care in the UK.
Study results published in Frontiers in Psychiatry in 2021 indicated that the ICA could successfully detect mild cognitive impairment and Alzheimer’s dementia across two separate populations, reliably differentiating between healthy cognition, MCI, and Alzheimer’s at more than 80-percent accuracy. Peer-reviewed, updated results were published in August 2023 and the test is still in use in the UK as well as in the U.S. and Middle East.
Despite the accessibility and speed of this test, it hasn’t been enough to revolutionize Alzheimer’s care in the UK, where dementia affects around 900,000 people — predicted to rise to 1.4 million by 2040.
“Significant investment is needed to ensure the NHS has the right tools to identify people with dementia much earlier than it is currently able to,” Kohlhaas said. “Low-cost tools like blood tests that are non-invasive and simpler to administer than current gold-standard methods are the answer to this. But we need to move these tests out of the lab and assess their effectiveness in real-world settings like the NHS.”
The current landscape of innovation for blood-based dementia diagnostics
To fill this gap, several blood tests for Alzheimer’s disease are underway. Blood tests for dementia are already available in private clinics in the U.S. and Hong Kong (see: Quest’s new blood based Alzheimer’s risk test) — but, patients may pay a significant amount for early detection… and results may not be so reliable. Researchers in the UK emphasize the need for more work to ensure that blood tests accurately measure the right combination of biomarkers without providing false results.
One test — biopharma company C2N Diagnostics’ PrecivityAD® — is fairly far along the pipeline: It is approved for use by doctors in the U.S. for people who show Alzheimer’s symptoms, has also received approval for safety in the European Union. When patients display cognitive symptoms, doctors send a blood sample to the company, which assesses the ration of Alzheimer’s biomarker protein beta-amyloid in the blood.
This test also looks at another protein, apolipoprotein E — the protein related to genetic variant ApoE4, sometimes called the “Alzheimer’s gene” — to assess an individual’s genetic susceptibility to Alzheimer’s. (This protein is also linked to a higher risk of brain bleeds as a side effect from newly FDA-approved monoclonal antibody drugs for Alzheimer’s, Aduhelm and Leqembi.) Then, using a computer program, PrecivityAD’s testing process factors in the levels of these substances and the patient’s age, producing a score that shows the likelihood of having Alzheimer’s. The results come back in a few days. If the score is high, it means the person is likely to have Alzheimer’s disease.
The UK initiative aims to develop tests that look for specific proteins occurring before dementia symptoms appear. The urgency for blood tests has intensified since the discovery of medicines that can slow cognitive decline. Billionaires have teamed up with foundations and put hundreds of millions of dollars into the push for new diagnostics. Meanwhile, pharmaceutical firms Roche and Eli Lilly — developing early-stage Alzheimer’s treatments for which blood tests could be greatly useful in determining patient eligibility — are also joining forces to develop an Alzheimer’s blood test.
Works in progress
There are some limitations for these tests. Right now, the range of these tests only check for a couple specific biomarkers linked to Alzheimer’s disease. This means they might miss signs of other types of dementia — or, they might only give information about one part of Alzheimer’s. So, if test results come back negative for Alzheimer’s, but the test taker is still having memory problems or other worrying symptoms, they should consult with their doctor, experts say, as there’s a chance they could have a different kind of dementia, a non-Alzheimer’s-driven case of cognitive impairment driven by some other health issue (which could be reversible depending on the underlying cause).
On the flip side, if someone without any symptoms takes the test and it shows unusual results, it might cause unnecessary concern, experts say. “Although these tests are useful in investigating the possibility of having Alzheimer’s disease, using them in isolation is still not as accurate as the tests currently used by qualified doctors,” wrote University College London colleagues Eleftheria Kodosaki, a UCL neuroimmunology research fellow, and Deborah Alawode, a PhD student, in an Alzheimer’s blood test explainer.
PrecivityAD in particular has been used in a number of clinical studies so far, and it often matches with signs of Alzheimer’s disease. However, it’s not always 100-percent accurate — and it can’t tell exactly how the disease will progress in that person.
While testing has been relatively extensive for such a new technology, experts watching this space say there’s still more data needed to be confident about its ability to detect Alzheimer’s before it gets rolled out too widely:
“Studies that have used this test also excluded certain participants (such as those with chronic health conditions) to avoid affecting how the test’s results were interpreted,” Kodosaki and Alawode wrote. “The majority of the participants were also white. This makes it uncertain how accurate these tests will be for people of diverse backgrounds or those with other health conditions.”
Indeed, experimental diagnostic methods including blood tests are being found to be less effective in diagnosing the disease in different racial ethnicities as they are in white people — because Alzheimer’s seems to effect different racial groups differently, and trials don’t reflect the diversity of the population confronting the disease.
Beyond reliability, experts say making sure they’re accessible to all will be the other big challenge — especially in places without comprehensive socialized medical programs.
They added: “It’s clear that exciting advancements are happening in the field to make Alzheimer’s disease diagnoses more accessible and accurate. Once these tests are refined to improve accuracy, they could offer new hope to patients – allowing them to be diagnosed and treated in the early stages of the disease.”