New research indicates that blood-based biomarker tests significantly improve diagnostic precision for primary care physicians, reaching levels previously limited to specialized clinics.
Blood test results allow primary care physicians to diagnose Alzheimer’s disease with nearly the same accuracy as specialists, according to data reported at the Alzheimer’s Association International Conference (AAIC) 2026.
In a real-world study involving more than 1,300 patients and 165 physicians, researchers found that a blood-based biomarker test improved the accuracy of Alzheimer’s diagnosis in both primary and specialty care settings. The test measures amyloid beta and phosphorylated tau, which are abnormal brain proteins associated with the disease.
The interim results included 1,310 patients with mild cognitive impairment or dementia in Sweden. Among those evaluated in primary care, physicians’ diagnostic accuracy rose from 65% before receiving blood test results to 93% after. Specialists saw their diagnostic accuracy rise from 74% to 89% after receiving the results. In a head-to-head comparison, both primary care physicians and dementia specialists achieved approximately 90% accuracy.
“We wanted to find out whether a simple blood test for Alzheimer’s changes how doctors actually diagnose and manage their patients in everyday clinical care,” says Sebastian Palmqvist, lead author of the study, neurologist and associate professor of neurology at Lund University, Sweden, in a release. “Accurate Alzheimer’s diagnosis has largely been limited to specialist settings. Our findings show that this blood test could bring that level of accuracy into primary care, where most patients are first seen, closing the gap between primary care and specialty care.”
Impact on Clinical Decision-Making
The researchers used the PrecivityAD2 blood test to measure the impact on clinical management. After reviewing the test results, physicians changed their diagnoses for approximately one-third of patients. Furthermore, care plans and future examination schedules were revised for more than half of the patients.
The study found the blood test was particularly effective in primary care for ruling out Alzheimer’s disease. Primary care clinicians increased their willingness to rule out the disease from 12.9% to 25% following a negative test result.
“A negative result helped primary care physicians confidently rule out Alzheimer’s and look for other causes of the symptoms,” says Palmqvist in a release.
Improving Access to Diagnosis
Currently, the standard of care for confirming Alzheimer’s disease requires specialized tools such as amyloid positron emission tomography (PET) scans or cerebrospinal fluid analysis. These methods are often expensive and limited to specialized memory clinics.
“The results suggest highly accurate blood tests can change — even improve — diagnosis and medical management in primary and secondary care, meaning doctors all along the care continuum may find them useful. This study strongly suggests there is great clinical utility for this test,” says Sheena Aurora, MD, Alzheimer’s Association vice president of medical affairs, in a release.
To assist clinicians, the Alzheimer’s Association is developing a decision-making tool for its professional resource hub. The organization has also published Clinical Practice Guidelines that offer evidence-based, brand-agnostic recommendations for using blood tests in specialty care for patients with dementia symptoms.
“Because not all blood-based biomarker tests meet the same standards for accuracy, clear evidence-based guidance is essential,” says Aurora in a release. “These tools help clinicians make informed decisions about using the right blood-based biomarker test for the right patient at the right time.”
