Alzheimer’s Blood Tests: Most Patients Are Not Afraid to Know

Primary care patients educated about Alzheimer’s disease blood-based biomarkers were generally willing to undergo tests and supported their use, survey data showed.

After patients received a brief explanation of Alzheimer’s blood tests, 94.5% supported offering them to patients with memory complaints, and 85% said they were willing to complete a test if their clinician recommended it, reported Andrea Russell, PhD, of Northwestern University Feinberg School of Medicine in Chicago, and co-authors.

Patients endorsed Alzheimer’s blood tests when they informed medical care (94.2%), were covered by insurance (93.4%), if comprehensive education was received prior to testing (88.5%), and if testing was easy or convenient (88.1%), Russell and colleagues wrote in Alzheimer’s & Dementia.

Barriers to Alzheimer’s blood tests included cost (49.3%), concerns about test reliability (35.3%), concerns about being treated differently after a positive test (24.2%), and fears of a positive result (21.7%).

Participants strongly or somewhat agreed that these concerns and fears would be a barrier to testing, Russell noted. “Yet, 85% said they would undergo testing, suggesting those concerns may not be deal-breakers,” she told MedPage Today.

“There is a lot of fear out there about dementia, and doom and gloom around the diagnosis, because there is no curative treatment,” Russell observed.

“I’ve encountered patients who would prefer not to know if they have dementia,” she said. “However, I’ve seen many people experiencing memory concerns who might be worried about what is causing changes — normal aging versus mild impairment versus dementia — who still pursue testing so they have an explanation for their symptoms.”

A diagnosis can link patients to support, resources, and complementary treatments, which patients and families see value in, she added.

“There are important benefits and limitations to the use of blood-based biomarkers that patients need to be aware of,” Russell pointed out. “Our survey indicated patients would want comprehensive education before testing, as well as to understand how the results would impact care. Clinicians should be prepared to have these shared decision-making conversations.”

Blood-based biomarkers have shown promise as tools for detecting Alzheimer’s pathology, noted Maria Carrillo, PhD, of the Alzheimer’s Association in Chicago, who wasn’t involved with the study. “Blood-based biomarker tests could improve the accuracy and speed of diagnosis when used as a complement to other testing, offering a path to earlier Alzheimer’s detection,” she told MedPage Today.

In May 2025, the FDA cleared the first blood-based diagnostic test to detect amyloid plaques associated with Alzheimer’s disease in people with symptoms. In October, the agency cleared a plasma phosphorylated tau 181 (p-tau181) test to help rule out Alzheimer’s-related amyloid pathology in primary care.

Lab-developed tests not approved by the FDA also are on the market. Last year, the Alzheimer’s Association issued guidance outlining strict sensitivity and specificity parameters for Alzheimer’s blood tests to either triage or diagnose people with cognitive impairment.

“Due to uncertainty around the diagnostic accuracy of blood-based biomarkers in primary care settings — which often consists of a more heterogeneous patient population — the guideline focused on specialized care settings, with plans to gradually expand to other settings, including primary care, as evidence evolves,” Carrillo explained.

Studies have not assessed primary care patients’ views on Alzheimer’s biomarkers, Russell and colleagues noted. To address this, the researchers surveyed adults from Chicago-area clinics who were in one of three ongoing cohort studies who agreed to be contacted for ancillary research.

Overall, 1,431 people were contacted to participate; of those, 572 completed the 15-minute questionnaire. Most participants (83.8%) were unfamiliar with Alzheimer’s blood tests, and 1.8% had previously completed testing.

As part of the survey, all participants received brief information that explained how Alzheimer’s blood tests could be used in primary care.

Survey respondents had a mean age of 62 years and 63.8% were women. Just over half (54.8%) were white, 27.7% were Black, and 10.7% were Latino. Almost a third (32%) had less than a college degree. Nearly half (47.5%) had three or more chronic conditions. Most said they had either good (61.2%) or excellent (16.7%) overall memory.

If their Alzheimer’s test were positive, 87% of patients said they would try to improve their brain health. Nearly 73% said they would expect emotional distress after a positive result.

People who completed the survey were more likely to be at risk for Alzheimer’s disease than non-completers, Russell and colleagues acknowledged. The study cohort had participated in other research and may be more open to Alzheimer’s blood tests than other groups.

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