Study in Frontiers in Neurology Affirms Amyloid Blood Test Can Help Identify Patients Who May Forgo Imaging Evaluation for Alzheimer's Disease

Rhea-AI Summary

Quest Diagnostics, in collaboration with the University of Florida and Mount Sinai Medical Center, has developed a blood test that can potentially reduce the need for PET imaging in patients with mild cognitive impairment, aiding in the diagnosis of non-Alzheimer's disease causes and cutting healthcare costs.

Positive

• The study suggests that a blood test analyzing amyloid protein levels can indicate that Alzheimer's disease is likely not the cause of mild cognitive decline.
• Researchers found that up to 99% of patients with negative amyloid protein results on PET scans would also have negative results on the blood test evaluating Aβ42/40 ratio.
• The test's high predictive accuracy could lead to a reduction in PET brain scan evaluations, allowing for a more focused therapeutic approach and cost savings in healthcare.
• The collaboration between Quest Diagnostics, the University of Florida, and Mount Sinai Medical Center highlights the potential of mass spectrometry-based blood tests in improving diagnostic processes for cognitive disorders.

Negative

• None.

Medical Research Analyst

The introduction of a blood test for Alzheimer's disease using amyloid protein levels presents a transformative shift in the diagnostic landscape. From a research perspective, the reliability of such a test, as indicated by its ability to predict negative PET imaging results, could significantly streamline the diagnostic process. The implications of this are multifaceted. Primarily, it could lead to a reduction in the reliance on PET scans, which are not only costly but also less accessible due to limited availability of PET facilities. This shift could democratize the initial assessment phase for cognitive impairment, making it more accessible and cost-effective.

Furthermore, the financial implications for healthcare providers and payers are considerable. By reducing unnecessary PET scans, there is potential for substantial cost savings. This could also impact the business models of companies that specialize in PET imaging, as well as those developing blood-based diagnostic tests. The ripple effect of such a diagnostic tool extends to pharmaceutical companies involved in the development of Alzheimer's treatments, as it could refine patient selection for clinical trials, potentially leading to more targeted and efficient research and development.

Healthcare Economist

From an economic standpoint, the adoption of a blood test for Alzheimer's diagnosis could represent a shift in healthcare resource allocation. If the test is as effective as suggested, it could alleviate the financial burden on the healthcare system by reducing the number of expensive PET scans. This could lead to a reallocation of resources towards other areas of need within the healthcare system. Additionally, the potential increase in early and accurate diagnosis may lead to earlier interventions, which could slow disease progression and reduce long-term care costs.

However, it is important to consider the market dynamics. The widespread use of this test could disrupt the market for PET imaging, potentially leading to job losses in that sector. Conversely, there could be an uptick in the demand for professionals trained in the interpretation of these new blood tests. It's also essential to monitor the pricing strategies of the companies offering these tests to ensure they remain affordable and do not create a barrier to access.

Healthcare Policy Analyst

Implementing a blood test for Alzheimer's has policy implications that extend beyond cost savings. It raises questions about insurance coverage and reimbursement policies, which will need to be updated to reflect this new diagnostic tool. Ensuring equitable access to the test will be a key concern for policymakers, especially given the potential to reduce healthcare disparities by providing a less expensive and more accessible diagnostic option.

Additionally, there is a broader impact on public health policy. With an aging population and the prevalence of Alzheimer's disease expected to rise, early and accurate diagnosis is critical for planning and allocating resources effectively. The integration of this test into standard care protocols could also prompt revisions to guidelines for the management of cognitive impairment, potentially leading to more personalized and effective treatment strategies.

Findings suggest the test can reduce the need for PET imaging in some patients with mild cognitive decline to enable therapeutic focus on non-Alzheimer's disease causes, broadening access to quality evaluation and lowering healthcare costs

SECAUCUS, N.J., March 26, 2024 /PRNewswire/ -- A blood test that analyzes levels of amyloid proteins by highly sensitive mass spectrometry could help physicians establish that Alzheimer's disease (AD) is likely not the cause of patients' mild cognitive impairment, finds a new study published in Frontiers in Neurology by researchers from Quest Diagnostics (NYSE: DGX), the University of Florida and Mount Sinai Medical Center in Miami Beach.

According to the analysis, up to 99% of patients with a negative result for amyloid proteins in the brain using an imaging procedure called positron emission tomography (PET) would likely be negative using a blood test that evaluates a ratio of amyloid beta 42 and 40 proteins (Aβ42/40), which are found in the brain and also circulate in the blood stream. With this level of prediction, the investigators determined the test could help reduce PET brain scan evaluations by about 40%, with potentially substantial savings in healthcare costs for these patients.

While amyloid PET imaging is an established method for aiding diagnosis of AD, it is significantly more expensive, invasive and specialist-dependent than blood tests.

"The findings of this analysis in a large cohort have significant implications for AD care management, because they potentially mean many patients could benefit from this type of blood-based assay that has advantages relative to current approaches," said co-author David E. Vaillancourt, PhD, Orchid Professor and Chair Applied Physiology and Kinesiology, College of Health and Human Performance, Fixel Institute of Neurological Disorders and Director, 1Florida ADRC Biomarker Core.

The study, Clinical utility of plasma Aβ42/40 ratio by LC-MS/MS in Alzheimer's disease assessment, is believed to be one of the largest published studies to evaluate amyloid blood testing for AD assessment. The investigators analyzed 6,192 deidentified laboratory test results from patients whose physicians submitted specimens for testing by Quest's Aβ42/40 ratio test (brand name Quest AD-Detect® Beta-amyloid ratio testAΒ42/40). Clinical performance of the Quest test was established using 250 specimens from participants with amyloid PET imaging and demographic data from the 1Florida Alzheimer's Disease Research Center. Quest introduced the AD-Detect™ test to physicians in early 2022.

The investigators also evaluated the performance of the blood test by different interpretative ranges based on different cutoffs, or amyloid levels in the blood. Proposed guidelines from the National Institutes of Aging recommend blood biomarker testing account for different ranges by cutoff levels, including an intermediate range, to support clinical decision making.

Key findings:

High NPV across populations: The test's negative predictive value (NPV) was 99% (at the highest cutoff of 0.170) in a population with moderate prevalence of AD (40%) as determined by PET-positivity. NPV represents the likelihood a disease is not present in a given population. The investigators then applied the NPV of 99% to the population of 6,192 deidentified specimens tested by Quest for Aβ42/40. They determined that 40% of that population could reliably forgo additional evaluation by PET, which costs about $5,000 per scan.

High sensitivity for AD PET-positivity at lower cut off: The test was 91% sensitive for detecting AD, as determined by PET scan at a cutoff of 0.160 in a population with moderate prevalence of PET-positivity of 40%.

In the same population and cutoff, the specificity was 76%. The same investigative team recently published results of a study in Alzheimer's & Dementia that showed the "novel and important" finding that abnormal Aβ42/40 blood testing "associates with quantifiable changes in the tissue and extracellular microstructural environments" of the brain, even in PET-negative patients.

"These findings show Aβ42/40 testing is very helpful in identifying amyloid pathology in populations with a high prevalence of AD, particularly older individuals," said study co-author Michael Racke, MD, Medical Director of Neurology at Quest Diagnostics. "We believe the comparatively low specificity reflects the limits of PET scans to identify the earliest stages of AD pathology and that many of these patients will progress to be PET-positive as the disease worsens."

APOE4 did not influence accuracy, possibly due to population diversity: APOE4 alleles did not substantially improve accuracy of the Aβ42/40 test, in contrast to other research. Investigators theorize this was due to a higher than typical percentage of patients of Hispanic heritage in the study population. APOE4 is a genetic trait that raises risk of AD and is more likely to correlate with PET-positive results in patients who are White than Hispanic.

"Our findings are a cautionary note that algorithms incorporating Aβ42/40 and APOE4 allele status may not be generally applicable for all races and ethnicities," wrote the authors.

Nearly 7 million Americans have Alzheimer's, the most prevalent dementia, a number projected to reach 14 million by 2060. New blood tests offer the potential for primary care physicians as well as specialists to identify people at risk for Alzheimer's disease even before symptoms manifest.

To access the complete study, including methodology, strengths and limitations: Frontiers | Clinical utility of plasma Aβ42/40 ratio by LC-MS/MS in Alzheimer's disease assessment (frontiersin.org)

About Quest Diagnostics
Quest Diagnostics works across the healthcare ecosystem to create a healthier world, one life at a time. We provide diagnostic insights from the results of our laboratory testing to empower people, physicians and organizations to take action to improve health outcomes. Derived from one of the world's largest databases of de-identifiable clinical lab results, Quest's diagnostic insights reveal new avenues to identify and treat disease, inspire healthy behaviors and improve healthcare management. Quest Diagnostics annually serves one in three adult Americans and half the physicians and hospitals in the United States, and our nearly 50,000 employees understand that, in the right hands and with the right context, our diagnostic insights can inspire actions that transform lives and create a healthier world. www.QuestDiagnostics.com.

 

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SOURCE Quest Diagnostics

How can the blood test developed by Quest Diagnostics potentially reduce the need for PET imaging?

The blood test analyzes amyloid protein levels to indicate if Alzheimer's disease is likely not the cause of mild cognitive decline, reducing the necessity for PET scans.

What is the significance of the Aβ42/40 ratio in the blood test?

The Aβ42/40 ratio helps evaluate amyloid proteins in the brain and blood, aiding in diagnosing non-Alzheimer's disease causes of cognitive impairment.

Who collaborated in the development of the blood test mentioned in the PR?

Quest Diagnostics, the University of Florida, and Mount Sinai Medical Center collaborated on the development of the blood test.

What percentage of patients with negative amyloid protein results on PET scans would also have negative results on the blood test?

Up to 99% of patients with negative amyloid protein results on PET scans would also have negative results on the blood test.

How could the blood test potentially lower healthcare costs?

By reducing the need for PET brain scan evaluations, the blood test allows for a more targeted therapeutic approach, leading to cost savings in healthcare.