Contributed Commentary by Ashton Harper, Roche Diagnostics
October 20, 2026 | New blood tests have the potential to transform how Alzheimer's disease is diagnosed. By reducing the need for costly scans and invasive lumbar punctures with a simple blood draw, these tests have the potential to bring accurate, early detection within reach for millions of patients during routine primary care visits. Yet, despite being approved in the US and more than 30 countries across Europe and Asia-Pacific, uptake in community practice remains limited.
While clinical practice guidelines for blood tests exist in specialist settings across markets such as the US, France, and China, no country has yet incorporated them into official primary care protocols. This creates a stark disconnect between technological capability and clinical reality: fewer than one in four primary care clinicians report using these tests for patients with suspected cognitive impairment. The barrier is not merely institutional; it is deeply practical. Many general practitioners report low confidence in diagnosing Alzheimer’s independently, a hesitation compounded by the historic scarcity of disease-modifying treatments (DMTs) that would make an early diagnosis actionable.
Bridging this gap requires robust clinical evidence demonstrating that these blood tests can be deployed safely and effectively in community care. Without real-world validation to bolster clinician confidence, even the most accurate test will remain underutilized. Fortunately, that evidence base is growing. Breakthrough studies from Sweden and the US, alongside ongoing global primary care trials, are demonstrating the value of blood tests in community practice, laying the groundwork for a true paradigm shift in the diagnosis and care of Alzheimer’s.
The Diagnostic Gap In Primary Care
Despite being clinically validated and approved for use, adoption of these blood tests has been slow in many parts of the world. Research presented at the American Geriatrics Society's 2026 meeting found that only 16.7% of primary care clinicians in the US reported routinely or sometimes ordering blood tests for suspected cognitive impairment. This compared with 71.1% for neuropsychological testing and 77.4% for CT imaging, and was similar to the rate for PET scans (18.4%). In the same survey, 72% of all clinicians rated blood test results a low priority in ongoing dementia care, with a further 18% unsure.
This is in part a question of confidence. In the same survey, over one-fifth (21.7%) of primary care clinicians reported low confidence in diagnosing dementia in older adults, a figure that jumps to 41.2% for Alzheimer's disease specifically. Unsurprisingly, clinicians with low confidence are significantly more likely to refer patients to specialists rather than initiate diagnostic testing themselves. This cautious approach is understandable. Many patients, particularly those over 65, present with subtle non-specific cognitive symptoms that may stem from a wide array of potential causes. However, when primary care diagnostic uncertainty collides with severe specialty care bottlenecks, the result is critical delay, leaving patients and families waiting far too long in the dark.
Qualitative studies among GPs in France and the Netherlands point to further reasons for reluctance. GPs in both countries said their priority is ruling out reversible causes of cognitive decline rather than confirming Alzheimer's specifically, and that in the absence of DMTs, they see limited benefit in distinguishing it from other causes of impairment. It is easy to see why: naming a disease this serious, when they feel there is little they can offer to help, is not a decision GPs take lightly. This is borne out by GPs in the French study, who described the word "Alzheimer's" itself as carrying a significant psychological burden for patients, often leading them to use less direct language when discussing a diagnosis. Tellingly, GPs in both studies said this situation would change with the arrival of DMTs.
Biomarkers In Primary Care Practice
Recent evidence suggests that the confidence gap narrows once GPs actually use these tools. In a study of more than 1,300 patients and 165 primary care physicians in Sweden, diagnostic accuracy rose from 65% to 93% after reviewing blood test results, nearly matching specialists' accuracy of 94%, also aided by the test, in the same patients. Physicians changed their diagnosis in 30% of cases after reviewing results, and revised clinical management in around half of cases, demonstrating a transformative shift in patient care. Testing proved particularly valuable in ruling out Alzheimer's: physicians' confidence in excluding the disease after a negative result nearly doubled from 12.9% to 25%.
A smaller study of 20 US primary care physicians found a similar pattern. Almost all those interviewed saw a beneficial role for blood tests in their own practice, citing greater confidence diagnosing early Alzheimer's, reassurance for patients and families, and support for care planning as key benefits. Their main reservation was about reimbursement. Beyond that, they wanted clearer guidance on where testing should sit in the diagnostic sequence, and around half said their motivation to diagnose early would grow as DMTs become more widely available.
The broad and equitable availability of safe, effective and convenient DMTs is the ultimate goal. However, while we work toward that future, we must not overlook a vital fact: early, clear diagnosis is crucial today for patients, families, healthcare systems, and the advancement of research.
A recent randomized trial in Spain found that sharing blood test results earlier in memory clinics increased high-confidence diagnoses tenfold for early rather than late disclosure. It also led to earlier treatment and faster discharge back to primary care—all without increasing patient anxiety or distress.
Early diagnosis significantly improves everyday care. Research commissioned by organizations like the UK Alzheimer’s Society shows that individuals with undiagnosed dementia visit Emergency Departments (A&E) on average 1.5 times per year—three times as often as those without dementia, and noticeably higher than individuals with a formal diagnosis.
A formal diagnosis enables care teams to set up structured community support and caregiver oversight, stabilizing chronic health conditions before a crisis occurs. It also opens the door to symptom-managing treatments much sooner. One US analysis, showed that patients receiving these treatments had a 20% lower rate of admission into long-term care facilities. Furthermore, 2024 research by Carnal Farar and the Alzheimer’s Society in the UK estimated that diagnosing Alzheimer’s early enough to begin symptom-delaying treatment could save up to £44,887 per person.
Patients benefit too from simply understanding what is causing their symptoms: dementia has multiple possible causes, each with a different trajectory and management approach, and a clear diagnosis allows care to be tailored accordingly. For patients and families, a definitive diagnosis provides long-awaited answers for unexplained changes, while offering a critical window of time to make important legal, financial, and personal plans for the future.
Diagnosing early may also help to optimize patient safety. Because Alzheimer's disease affects brain chemistry (reduction in the neurotransmitter acetylcholine), prescribing certain routine medicines such as anticholinergics (block the action of acetylcholine; include medicines for allergies, sleep and bladder issues) to an undiagnosed patient can trigger acute confusion and rapid cognitive decline. A clear diagnosis ensures doctors avoid medications that could unintentionally cause harm.
Additionally, early identification creates an opportunity to slow cognitive decline through lifestyle changes. The landmark FINGER trial demonstrated that a combined approach focusing on diet, exercise, brain training, and cardiovascular health can help protect memory and thinking skills.
A confirmed biological diagnosis is also essential for clinical trial enrolment, granting patients access to emerging therapies. Alarmingly, a recent ARUK report highlighted that diagnostic delays often leave patients ineligible for these trials, which specifically target the earliest stages of the disease.
The case for early diagnosis will only grow stronger as new treatments arrive. A definitive diagnosis, whether through blood tests, spinal fluid analysis, or PET scans, is already required to access newer therapies. Building strong diagnostic capacity now ensures that testing delays won't stand between future patients and the care they need.
Building The Evidence Base In Primary Care
Further studies are now underway to understand how these tests perform when adopted into routine general practice. In Scotland, a study involving more than 50 GP practices and up to 500 patients is testing whether blood tests can help GPs to diagnose Alzheimer's more confidently and make better-informed decisions on further investigation and treatment. In Australia, a study across several major cities is examining GP understanding, confidence and management behavior before and after biomarker results become available.
Findings from studies like these will help to inform future guidance on the use of AD blood tests in primary care. The Alzheimer's Association recently introduced a decision-making checklist for primary care clinicians, to sit alongside its existing Clinical Practice Guidelines for specialty care. Advice on blood testing within this checklist covers the standard ‘cognitive lab panel’ (e.g., certain vitamin and hormone levels); however, it does not currently include new specific AD blood tests like pTau217. Insurance coverage for certain tests is also beginning to expand, helping to reduce cost as a barrier to access.
Some clinicians have cautioned that rapid adoption without sufficient education and guidance for primary care doctors could lead to overdiagnosis, unnecessary follow-up testing and misinterpretation of results, and that wider use in primary care could increase pressure on specialist services rather than ease it. These are risks that need to be monitored and managed as adoption grows, alongside the clinical trials already underway.
Blood tests represent a cornerstone in the future of Alzheimer's diagnosis and management. The imperative now is to accelerate the real-world evidence and clinician confidence required to integrate these tools into routine primary care at the urgency the disease demands, ensuring patients are identified early enough for therapeutic and lifestyle interventions to have maximum impact.
Ongoing initiatives across Sweden, Scotland, and Australia are actively building this foundation, yielding the data needed to shape official guidelines, clinician training, and decision-support tools. However, evidence alone is not enough. Translating these breakthroughs into everyday practice will require sustained investment and cross-sector collaboration among industry leaders, healthcare systems, professional societies, and payers. Only by aligning policy, reimbursement, and primary-to-specialty care pathways can we unlock the full potential of these new tests and deliver timely, transformative care to millions worldwide.
Ashton Harper is Global Medical Director, Neurosciences at Roche Diagnostics, providing strategic direction for Roche Diagnostics' rapidly growing neurology portfolio, focusing on evidence generation, external collaborations, medical education, and KOL engagement. Ashton joined Roche Diagnostics in August 2020 as the Head of Medical Affairs for the UK & Ireland, leading clinical research across various therapeutic areas, including oncology, cardiology, neurology, infectious diseases, critical care, and women’s health. Ashton studied medicine at University College London, earning both an MBBS and a B.Sc. in physiology and pharmacology. He worked as a doctor in the NHS and achieved membership in the Royal College of Surgeons. During his surgical training, he was awarded a postgraduate fellowship to the Cleveland Clinic in the USA to observe experts in inflammatory bowel disease. He can be reached out at ashton.harper@roche.com.