A new blood test looks highly accurate for diagnosing Alzheimer’s disease in the community, and comes alongside other promising developments for the brain disorder.

A blood test for Alzheimer’s disease biomarkers looks set to strengthen diagnostic accuracy among specialists and primary care doctors, according to a first-of-its-kind study.

The research centred on more than 1,300 patients with mild cognitive impairment or dementia, based in Sweden, and 165 doctors. It saw a head-to-head comparison after reviewing blood test results. In this, the primary care doctors and specialists both had a diagnostic accuracy of around 90%. For those in primary care, the test was most useful to rule out Alzheimer’s.

The real-world study’s data was revealed at the Alzheimer’s Association International Conference 2026 in London in July. It had measured amyloid beta and phosphorylated tau, abnormal brain proteins linked to Alzheimer’s.

After seeing the blood test results, doctors changed their diagnosis in about a third of their patients, also altering their plans for future care and exams for more than half of the patients.

The patients seen in primary care were also independently assessed by dementia specialists.

The test is more useful for ruling out Alzheimer’s than diagnosing it as primary care doctors tend to send patients for specialist confirmation. 

Current Alzheimer’s diagnosis includes specialist PET scans and spinal fluid analysis, but these are often expensive and only available in memory clinics. 

“It’s important to remember that these blood tests are designed specifically to detect Alzheimer’s, so patients with negative results may still have other neurological conditions and may still be suitable for referral to a specialist for further evaluation,” added Sebastian Palmqvist, study lead and associate professor of neurology at Lund University, Sweden.

Alzheimer's research

Further blood-based research

Palmqvist also announced the outcome of a study on the effects of Alzheimer’s blood-based biomarkers on diagnosis and clinical management in secondary and primary care.

Blood-based biomarkers for Alzheimer’s accurately detect pathology but still have an unclear impact on real-world clinical decision-making. So, his team assessed changes in diagnosis and clinical management for patients with cognitive impairment before and after their blood-based biomarker results were revealed to doctors in both primary and secondary care.

They analysed plasma prospectively using an algorithm called PrecivityAD2 and applied a two-cutoff model, classifying results as negative, intermediate or positive. Doctors then completed questionnaires before and after the blood-based biomarkers test disclosure. 

This found that in secondary care, dementia experts changed their diagnosis in 21.6% of patients after the test disclosure. Diagnostic accuracy for Alzheimer’s increased from 74% to 89%, and doctors’ readiness to make an immediate clinical diagnosis increased from 0.8% before to 11.5% after test disclosure in blood-based biomarkers-negative cases and from 1.9% to 55.4% in blood-based biomarkers-positive cases. Test disclosure also led to changes in clinical management in 49.2% of cases.

In primary care, diagnosis changed in 30.0% of patients. Accuracy for Alzheimer’s diagnosis increased from 65% to 93%, while readiness to make an immediate clinical diagnosis didn’t increase in blood-based biomarker-positive cases, whereas blood-based biomarker-negative results brought an increase from 12.9% to 25.0%. Changes in clinical management occurred in 55.9% of cases.

This showed how accessing a high-performing blood test substantially improves diagnostic accuracy for Alzheimer’s and leads to meaningful changes in clinical management in both primary and secondary care. Primary care doctors appear more confident using blood-based biomarker tests to rule out Alzheimer’s, whereas dementia experts also use them to support Alzheimer’s diagnosis.

UK research network launch

Finally, the UK has taken a stride towards new dementia treatments with the launch of the BARBARA Alliance, an initiative to improve dementia research. 

The nationwide platform will connect patients with clinical trials and aim to accelerate discoveries in the field.

BARBARA stands for the Brain Ageing Registry for Biomarkers, Access to trials, Research and Adoption, while the government also commissioned the Dame Barbara Windsor Dementia Goals Programme in 2022 to develop and deliver new treatments. 

The launch of the BARBARA Alliance is backed by the publication of a report, which sets out a roadmap for how the UK can become a global leader in dementia research and treatment.

The alliance will connect commercial Life Sciences companies, health foundations, charities, academics and national health systems.

It will be chaired by former Department of Health and Social Care minister Lord James Bethell and encourage innovations in biomarkers, clinical trials and data on innovative technologies, such as by advancing blood-based biomarkers.

It is the latest in a series of encouraging developments within Alzheimer’s detection.