The rise of blood-based biomarkers in primary care to assess cognitive decline

Among aging patients, cognitive complaints such as memory loss are increasingly common in primary care visits, driven by an aging population and growing awareness of Alzheimer’s disease. As a result, primary care providers are now on the front lines of cognitive health assessment. Yet for years, they have had limited tools to confidently evaluate early cognitive impairment without referring patients into complex, often delayed diagnostic pathways. 

Today, blood‑based biomarkers are changing that landscape, enabling Alzheimer’s disease evaluation to begin with a simple blood draw rather than immediate referrals, invasive testing, or advanced imaging. 

Rising demand and the need for clearer answers 

Historically, confirmation of Alzheimer’s pathology has relied on PET imaging or lumbar puncture. These procedures are costly, invasive, and can be difficult to access, leaving providers managing uncertainty during the earliest and most treatable stages of disease.  

With practical, scalable tools, primary care clinicians can better triage cognitive concerns and distinguish patients who require further evaluation from those who can be safely monitored over time. Blood-based biomarkers offer a more accessible path forward, enabling earlier biological insight while helping providers, patients, and families move from “watchful waiting” to informed, evidence-based decision-making. In this context, demand for Elecsys® pTau 181, the first blood test cleared by the FDA to aid in the initial assessment for Alzheimer's disease and other causes of cognitive decline in the primary care setting, is rising. 

Bringing validated biomarkers to primary care  

Labcorp is among the first to deliver FDA‑cleared blood‑based tests for Alzheimer’s disease biomarkers, such as pTau‑181, directly into everyday clinical practice. These tests offer providers and patients a simple option to aid in clinical assessments, including:  

Increasing adoption of blood-based biomarkers for neurological assessment 

Across the U.S., primary care providers managing neurological cases are embracing blood-based biomarker tests. In 2025 alone, Labcorp neurology testing volume in primary care grew significantly.  

Equally important is where adoption is taking place. Increasingly, blood‑based biomarker testing for neurological care is being used in community practices, rural clinics, and more, underscoring the real‑world accessibility of these tests. Adoption at this scale paves the way for a widely integrated model that helps evaluate the causes of cognitive decline in everyday care. 

But while clinical adoption of blood‑based biomarkers accelerates, formal guidelines for their use in primary care do not yet exist. This gap raises questions around patient selection, result interpretation, repeat testing, and how biomarker data should inform next steps. Concepts such as pretest probability play a critical role in these decisions, helping providers contextualize biomarker results within the broader clinical picture. However, until standard guidelines are established, biomarkers are best used as one component of a comprehensive assessment. 

What comes next for primary care and cognitive health 

The rise of blood-based biomarkers in primary care for cognitive symptoms reflects a growing need to perform assessments earlier and more effectively. As evidence expands and clinical guidance evolves, primary care providers play a central role in early Alzheimer’s detection, supported by biomarkers that enable clearer evaluation of cognitive decline. 

Labcorp is committed to making these breakthroughs widely accessible across the U.S. by working closely with researchers, clinicians, and organizations involved in clinical trials and drug development to advance both diagnostics and treatment.