Benefits of biomarker testing to diagnose early symptomatic Alzheimer’s disease

You are invited to view a special edition​ of “Inside Family Medicine” highlighting the use of blood-based biomarkers for Alzheimer’s disease (AD) in primary care settings, the value of early diagnosis, and effective workflow strategies for primary care teams.

The role of family physicians in AD detection

Family physicians are ideally situated to identify patients with AD. However, making an accurate clinical diagnosis of AD, especially in early symptomatic stages, is challenging. In a survey, lack of effective diagnostic tools in the primary care setting was among the top barriers to early diagnosis of mild cognitive impairment (MCI)/mild dementia due to AD.¹ Another study suggests primary care physicians are receptive to blood-based biomarker tests, but additional education around their use and interpretation could be beneficial.² With the availability of FDA-cleared blood tests for use in primary care, family physicians now have reliable diagnostic tools that can improve detection of AD at its earliest symptomatic stages.

Why use blood-based biomarkers to test for AD pathology in primary care?

Dementia is a broad term used to describe cognitive dysfunction and memory impairment severe enough to impact daily life. AD is the most prevalent form of dementia. In the United States, an estimated 7.4 million Americans older than 65 are living with Alzheimer's dementia in 2026.³ One challenge in dementia care is early detection. Studies have shown that only 8-11% of patients with MCI are detected in primary care.^4,5 The introduction of validated blood-based biomarker tests in primary care settings is expected to help with early symptomatic disease detection and streamline primary care to specialty care clinical workflows. Blood tests allow for the detection of biomarkers such as the pTau217 protein, which correlates with brain amyloid burden measured by amyloid PET.⁶ When validated in primary care, these tests can detect the likelihood of amyloid pathology in patients with signs, symptoms, or complaints of cognitive decline to aid in early AD diagnosis and guide referrals to specialists.⁷

How can early AD diagnosis benefit patients?

Alzheimer’s disease progresses along a continuum of stages, with cognitive symptoms worsening over time. The buildup of amyloid beta plaques in the brain is followed by elevated levels of phosphorylated tau (pTau217) protein in the cerebrospinal fluid (CSF) and blood.^8,9 FDA-approved amyloid-targeting therapeutic antibodies have been shown to slow the rate of cognitive decline.^10-13 Timely detection, referral, and AD diagnosis in the right therapeutic window (i.e., MCI and mild dementia) can allow patients eligible for amyloid-targeting therapies to navigate lifestyle changes and seek treatment before the disease progresses to later dementia stages.

How should blood-based biomarkers be used and implemented?

These tests should be used in the clinical contexts and patient populations for which they have been validated and cleared, as specified on their labels. Implementation requires clinicians to work with the dementia specialists at their institution to establish clinical workflows for assessment and referral. They should also work with the clinical laboratory to understand a test's intended use, performance, and limitations and how to interpret results.