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Dr. Richard Stefanacci explains why the FDA’s recent clearance of a diagnostic blood test for Alzheimer’s deserves celebration and critical examination.

The FDA’s recent clearance of the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio blood test for diagnosing Alzheimer’s disease represents a watershed moment in our decades-long battle against this devastating condition. As a geriatrician who has dedicated my career to improving care for older adults, of whom an increasingly large percentage are affected by dementia, I recognize this advancement as significant – yet it must be viewed within the broader context of a comprehensive patient journey.

Having been directly involved in clinical trials for Tacrine during my geriatric fellowship in 1992 – the first FDA-approved treatment for Alzheimer’s disease – as well as providing active care of older adults through PACE programs over the decades since, and serving as chief medical officer for TauRx, I’ve witnessed firsthand how slowly progress has come across the entire field of Alzheimer’s research. Despite more than 3 decades since that initial breakthrough, our advancements to date have been incremental at best. This sobering reality underscores why each step forward, including this new diagnostic tool, deserves celebration and critical examination.

Less Invasive Option for Alzheimer’s Diagnosis With Promising Accuracy

The newly approved test measures two key proteins – pTau217 and β-amyloid 1-42 – in human plasma and calculates their ratio to correlate with the presence or absence of amyloid plaques in the brain. With clinical study data showing 91.7% positive predictive value and 97.3% negative predictive value when compared to PET scan or CSF test results, this blood test offers a remarkably accurate yet significantly less invasive alternative to current diagnostic methods.

The test’s requirement of only a simple blood draw, rather than an invasive lumbar puncture or expensive PET scan, represents a democratization of AD diagnosis. This could dramatically increase access to accurate diagnosis, particularly in underserved areas and for patients who cannot easily access specialized care.

Beyond Amyloid: The Critical Role of Tau

While this blood test focuses on detecting amyloid pathology, it must be emphasized that Alzheimer’s disease involves complex pathophysiology beyond amyloid plaques alone. We must acknowledge the crucial role of tau neurofibrillary tangles, which more closely correlate with cognitive decline than amyloid deposition, especially given the controversy surrounding amyloid research and current treatment efficacy and safety.

The inclusion of pTau217 in this test is encouraging, though we must recognize that it functions as a downstream marker of tau pathology rather than a direct measure of tau aggregation itself. While some phosphorylated tau biomarkers in plasma show correlation with cognitive decline, research continues into more direct indicators of tau pathology, particularly mid-domain tau binding region (MTBR) tau sites that may more accurately reflect tau accumulation in the brain. Future diagnostic approaches should continue refining measurements of amyloid and tau pathology, while also acknowledging other contributing factors like neuroinflammation, synaptic dysfunction, and vascular changes.

The Complete Patient Journey: More Than Just a Test

While this blood test represents progress, we must remember that it’s merely one step in a complex journey. The patient pathway begins well before the test is ordered – it starts with awareness and concern about cognitive changes, followed by the decision by patient and provider to pursue testing.

The full journey includes:

1. Initial recognition and decision to test – Patient and professionals must acknowledge concerns and choose to investigate, overcoming stigma and fear that often delay diagnosis.
2. Proper test interpretation – Once results are available, healthcare professionals must accurately interpret findings within the clinical context, explaining implications to patients and families in understandable terms.
3. Appropriate treatment selection – Test results must guide evidence-based interventions tailored to the individual’s disease stage, overall health, and personal preferences.
4. Ongoing management and support – Beyond initial treatment, patients need continued monitoring, adjustment of care plans, and support for medical and non-medical aspects of living with Alzheimer’s.
5. Caregiver resources – Throughout this journey, family caregivers require education, respite options, and emotional support.

A comprehensive approach must incorporate earlier cognitive screening as a routine part of preventive care, clear staging systems that guide interventions, and patient-centered care planning through shared decision-making.

Transforming the Alzheimer’s Care Ecosystem

As we incorporate this new blood test into our clinical practices, we must simultaneously develop clinical guidelines for its appropriate use. Questions remain about who should be tested, when testing should occur, and how results should guide treatment decisions.

The true value of this diagnostic breakthrough will be realized when paired with effective treatments that can alter the disease course. Despite decades of research since my early involvement with Tacrine, progress in developing truly transformative treatments has been disappointingly slow. Recent advances in disease-modifying therapies targeting amyloid and tau give us reason for cautious optimism, but we must accelerate our efforts.

The FDA clearance of the Lumipulse test marks a significant step forward in simplifying and democratizing Alzheimer’s diagnosis. However, our ultimate goal must remain transforming the entire Alzheimer’s care ecosystem – from recognition and testing through accurate diagnosis to effective treatment and support – to improve outcomes and quality of life for the millions living with this condition and the many more who will face it in the future.

Any views and opinions expressed are those of the author(s) and/or participants and do not necessarily reflect the views, policy, or position of Physician’s Weekly, their employees, and affiliates.