Dementia stands as the United Kingdom’s most significant killer, tragically claiming over 75,000 lives annually. Despite its profound impact, diagnosis often proves challenging, typically occurring only after symptoms have become markedly pronounced. This critical delay, however, may soon be a thing of the past, thanks to a pioneering suite of new blood tests currently undergoing trials, designed to detect Alzheimer’s disease decades before any symptoms manifest.

The primary aspiration behind these revolutionary tests is to identify Alzheimer’s – the most prevalent form of dementia – sufficiently early to allow for proactive interventions. Such interventions could include adopting beneficial lifestyle changes, like consistent exercise and a healthy diet, alongside the administration of targeted pharmaceutical treatments, with the ultimate goal of halting the disease's progression. In the absence of a definitive cure, many scientists believe that this type of early, preventative action represents the most promising strategy for combating Alzheimer's disease effectively.

The scale of the challenge in the UK is stark: nearly one million people are currently living with dementia. Recent statistics underscore its severity, revealing that dementia is responsible for more fatalities than either cancer or cardiovascular disease. These deaths commonly result from complications arising from a compromised immune system, such as pneumonia, or from difficulties with swallowing. The issue of late diagnosis is compounded by the fact that approximately one in four individuals experiencing dementia symptoms delay seeking medical attention for two years or even longer. This reluctance often stems from the misconception that symptoms like forgetfulness or confusion are merely normal signs of ageing.

Presently, doctors rely on a combination of memory and cognitive function tests for Alzheimer’s diagnosis. These are complemented by advanced imaging techniques, including MRI and PET scans, which help identify characteristic signs of the disease, such as protein deposits or plaques in the brain. However, this emerging generation of blood tests promises to dramatically accelerate the diagnostic timeline, potentially by many years. While most of these tests currently necessitate blood samples drawn from an arm vein, some research teams are actively developing a more convenient finger-prick test, akin to those used by diabetes patients to monitor their blood glucose levels. This innovative approach would enable individuals to collect samples at home and post them to a laboratory for analysis.

Groundbreaking research from a team at Northwestern University in the United States has made a significant stride, identifying for the first time specific toxic proteins, designated ACU193+, in the brain. These proteins appear to play a pivotal role in the inflammation and cellular damage that are recognized hallmarks of early-stage Alzheimer’s. Reporting their findings in the journal Alzheimer’s & Dementia, the researchers revealed that these critical proteins can be detected in the bloodstream as much as two decades before the onset of symptomatic disease. Richard Silverman, a professor of chemistry at Northwestern and the study's senior author, emphasized the urgency of early intervention, stating to Good Health, “It’s important to be treated before symptoms appear because by then much neurodegeneration has already occurred. The promise of better early diagnostics before symptoms are apparent – combined with a drug that could stop the disease in its tracks – is the goal.”

The therapeutic landscape for Alzheimer's includes older medications such as cholinesterase inhibitors (e.g., Aricept), which have been available for years. These drugs function by enhancing the activity of acetylcholine, a vital chemical messenger in the brain essential for memory and learning, thereby easing symptoms and improving patients' quality of life, though they do not offer a cure. More recent pharmaceutical developments, including lecanemab and donanemab, demonstrate the ability to slow the disease's progression in its early stages, once symptoms have begun to manifest. However, these newer drugs have not yet received approval for use within the NHS, primarily due to concerns that their benefits may be too modest to justify their considerable cost, as well as the potential for serious side-effects like brain bleeds and swelling.

Intriguingly, the same Northwestern team behind the ACU193+ blood test has also discovered a novel drug, NU-9. This compound is already an established treatment for motor neurone disease, an incurable condition leading to the loss of muscle control. Experiments have shown that NU-9 can successfully "turn off" the toxic ACU193+ proteins in mice. This discovery is generating considerable optimism that NU-9 could potentially prevent, or at least significantly delay, the onset of Alzheimer’s disease in humans.

Concurrently, another promising blood test, known as the Fujirebio Lumipulse assay, has been deployed in a clinical setting, used on an estimated 1,000 individuals at University College Hospital in London. Physicians there are utilizing this assay to search for a specific protein called pTau217, which serves as a reliable indicator of Alzheimer’s disease hallmarks in the brain, including both tau tangles and amyloid plaques. Jonathan Schott, a professor of neurology at the University College London Institute of Neurology and a researcher involved in studies on pTau217, notes, “There are hundreds of potential biomarkers, but pTau217 is definitely one of the most promising.” He participates in a research program, supported by UK dementia charities, dedicated to investigating various potential blood tests. Professor Schott highlighted the extraordinary sensitivity of these new tests to Good Health, explaining, “To give you some idea of how sensitive these tests are, if you threw a grain of salt into an Olympic-sized swimming pool, these tests would detect it.” He further confirmed that a clinical trial for pTau217 is currently underway in memory clinics, with the aim of providing the necessary evidence for the National Institute for Health and Care Excellence to sanction their routine availability across the NHS.

While the routine adoption of blood tests, such as the one under development at Northwestern University, is still "some way off," according to Dr. Richard Oakley, associate director of research and innovation at the Alzheimer’s Society, their potential is immense. Speaking to Good Health, Dr. Oakley stated, “They could transform how Alzheimer’s disease is diagnosed. Getting an accurate diagnosis currently takes far too long and one in three people in the UK with dementia do not have a diagnosis. With new treatments on the horizon, early and accurate diagnosis must be a priority.” The advent of these highly sensitive blood tests offers a powerful new weapon in the fight against Alzheimer’s, promising a future where early detection and intervention could drastically alter the disease’s trajectory and improve countless lives.