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University of Gothenburg Study Findings Affirm Accuracy of Clinical Laboratory Blood Test to Diagnose Alzheimer’s Disease

Mar 4, 2024 | International Laboratory News, Laboratory Instruments & Laboratory Equipment, Laboratory Management and Operations, Laboratory Testing

Already-existing clinical laboratory blood test may be new standard for detecting Alzheimer’s biomarkers

In Sweden, an independent study of an existing blood test for Alzheimer’s disease—called ALZpath—determined that this diagnostic assay appears to be “just as good as, if not surpass, lumbar punctures and expensive brain scans at detecting signs of Alzheimer’s in the brain,” according to a report published by The Guardian.

Alzheimer’s disease is one of the worst forms of dementia and it affects more than six million people annually according to the Alzheimer’s Association. Clinical laboratory testing to diagnose the illness traditionally involves painful, invasive spinal taps and brain scans. For that reason, researchers from the University of Gothenburg in Sweden wanted to evaluate the performance of the ALZpath test when compared to these other diagnostic procedures.

Motivated to seek a less costly, less painful, Alzheimer’s biomarker for clinical laboratory testing, neuroscientist Nicholas Ashton, PhD, Assistant Professor of Neurochemistry at the University of Gothenburg, led a team of scientists that looked at other common biomarkers used to identify changes in the brain of Alzheimer’s patients. That led them to tau protein-based blood tests and specifically to the ALZpath blood test for Alzheimer’s disease developed by ALZpath, Inc., of Carlsbad, Calif.

The researchers published their findings in the journal JAMA Neurology titled, “Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology.”

In their JAMA article, they wrote, “the pTau217 immunoassay showed similar accuracies to cerebrospinal fluid biomarkers in identifying abnormal amyloid β (Aβ) and tau pathologies.”

In an earlier article published in medRxiv, Ashton et al wrote, “Phosphorylated tau (pTau) is a specific blood biomarker for Alzheimer’s disease (AD) pathology, with pTau217 considered to have the most utility. However, availability of pTau217 tests for research and clinical use has been limited.”

Thus, the discovery of an existing pTau217 assay (ALZpath) that is accessible and affordable is a boon to Alzheimer’s patients and to the doctors who treat them.

“The ALZpath pTau217 assay showed high diagnostic accuracy in identifying elevated amyloid (AUC, 0.92-0.96; 95%CI 0.89-0.99) and tau (AUC, 0.93-0.97; 95%CI 0.84-0.99) in the brain across all cohorts. These accuracies were significantly higher than other plasma biomarker combinations and equivalent to CSF [cerebrospinal fluid] biomarkers,” an ALZpath press release noted.

“This is an instrumental finding in blood-based biomarkers for Alzheimer’s, paving the way for the clinical use of the ALZpath pTau217 assay,” stated Henrik Zetterberg, MD, PhD (above), Professor of Neurochemistry at the University of Gothenburg and co-author of the study. “This robust assay is already used in multiple labs around the globe.” Clinical laboratories may soon be receiving doctors’ orders for pTau217 blood tests for Alzheimer’s patients. (Photo copyright: University of Gothenburg.)

Study Details

Ashton’s team conducted a cohort study that “examined data from three single-center observational cohorts.” The cohorts included:

“Participants included individuals with and without cognitive impairment grouped by amyloid and tau (AT) status using PET or CSF biomarkers. Data were analyzed from February to June 2023,” the researchers wrote. 

These trials from the US, Canada, and Spain featured 786 participants and featured “either a lumbar puncture or an amyloid PET scan to identify signs of amyloid and tau proteins—hallmarks of Alzheimer’s disease,” The Guardian reported, adding that results of the University of Gothenburg’s study showed that the ALZpath pTau217 blood test “was superior to brain atrophy assessments, in identifying signs of Alzheimer’s.”

“80% of individuals could be definitively diagnosed on a blood test without any other investigation,” Ashton told The Guardian.

Diagnosis Needed to Receive Alzheimer’s Disease Treatments

“If you’re going to receive [the new drugs], you need to prove that you have amyloid in the brain,” Ashton told The Guardian. “It’s just impossible to do spinal taps and brain scans on everyone that would need it worldwide. So, this is where the blood test [has] a huge potential.”

Even countries where such drugs were not yet available (like the UK) would benefit, Ashton said, because the test, “Could potentially say that this is not Alzheimer’s disease and it could be another type of dementia, which would help to direct the patient’s management and treatment routine.”

However, Ashton himself noted the limitations of the new findings—specifically that there is no success shown yet in Alzheimer’s drugs being taken by symptom-free individuals.

“If you do have amyloid in the brain at 50 years of age, the blood test will be positive,” he said. “But what we recommend, and what the guidelines recommend with these blood tests, is that these are to help clinicians—so someone must have had some objective concern that they have Alzheimer’s disease, or [that] their memory is declining,” he told The Guardian.

Experts on the Study Findings

“Blood tests could be used to screen everyone over 50-years old every few years, in much the same way as they are now screened for high cholesterol,” David Curtis, MD, PhD, Honorary Professor in the Genetics, Evolution and Environment department at University College London, told The Guardian.

“Results from these tests could be clear enough to not require further follow-up investigations for some people living with Alzheimer’s disease, which could speed up the diagnosis pathway significantly in future,” Richard Oakley, PhD, Associate Director of Research and Innovation at the Alzheimer’s Society, UK, told The Guardian.

Though Oakley found the findings promising, he pointed out what should come next. “We still need to see more research across different communities to understand how effective these blood tests are across everyone who lives with Alzheimer’s disease,” he said.

“Expanding access to this highly accurate Alzheimer’s disease biomarker is crucial for wider evaluation and implementation of AD blood tests,” the researchers wrote in JAMA Neurology.

“ALZpath makers are in discussions with labs in the UK to launch it for clinical use this year, and one of the co-authors, Henrik Zetterberg, MD, PhD, Professor of Neurochemistry at the University of Gothenburg, is making the assay available for research use as part of the ‘biomarker factory’ at UCL,” The Guardian reported.

In the US, to be prescribed any of the available Alzheimer’s medications, a doctor must diagnose that the patient has amyloid in the brain. A pTau217 diagnostic blood test could be used to make such a diagnosis. Currently, however, the test is only available “for research studies through select partner labs,” Time reported.

“But later this month, doctors in the US will be able to order the test for use with patients. (Some laboratory-developed tests performed by certain certified labs don’t require clearance from the US Food and Drug Administration.),” Time added.

It may be that the University of Gothenburg study will encourage Alzheimer’s doctors in the UK and around the world to consider ordering pTau217 diagnostic blood tests from clinical laboratories, rather than prescribing spinal taps and brains scans for their Alzheimer’s patients.

—Kristin Althea O’Connor

Related Information:

New Study Published in JAMA Neurology Affirms High Diagnostic Accuracy of ALZpath’s pTau217 Test in Identifying Amyloid and Tau in the Brain

Blood Test Could Revolutionize Diagnosis of Alzheimer’s, Experts Say

Simple Blood Tests for Dementia to Be Trialed in NHS

A Blood Test for Alzheimer’s Disease Is Almost Here

Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology

Alzheimer’s Disease Facts and Figures

Scientists Develop Blood Test for Alzheimer’s Disease

Clinical Laboratory Test for Alzheimer’s Disease Gets Ever Closer to Reality

Aug 23, 2019 | Instruments & Equipment, Laboratory Instruments & Laboratory Equipment, Laboratory News, Laboratory Pathology, Laboratory Testing

Scientists worldwide engaged in research to develop a biomarker for dementia are predicting success, though some say additional research will be needed

Could a blood test for Alzheimer’s disease soon be on clinical laboratory test menus nationwide? Perhaps so. A recent Associated Press (AP) article that was picked up by NBC News and other healthcare publications reported that experimental test results presented during the Alzheimer’s Association International Conference (AAIC) in July suggest the Holy Grail of dementia tests—one where the specimen can be collected in a doctor’s office during a routine screening exam—may be close at hand.

The AP story noted that “half a dozen research groups gave new results on various experimental tests, including one that seems 88% accurate at indicating Alzheimer’s risk.” And Richard Hodes, MD, Director of the National Institute on Aging, told AP, “In the past year, we’ve seen a dramatic acceleration in progress [on Alzheimer’s tests]. This has happened at a pace that is far faster than any of us would have expected.”

This could be a boon for medical laboratories seeking way to contribute more value to patient care. Especially among Alzheimer’s patients, who account for as many as 70% of all dementia cases.

Plasma Biomarker for Predicting Alzheimer’s

One of the experimental blood tests presented at the AAIC involved a 2018 study into “the potential clinical utility of plasma biomarkers in predicting brain amyloid-β burden at an individual level. These plasma biomarkers also have cost-benefit and scalability advantages over current techniques, potentially enabling broader clinical access and efficient population screening,” the researchers stated an article they published in Nature.

Dark Daily reported on this study in “Researchers in Two Countries Develop Blood Tests That Detect Alzheimer’s Decades Before Symptoms Appear; Could Eventually Give Clinical Laboratories a Diagnostic Tool,” June 4, 2018. The test “measures abnormal versions of the protein [amyloid beta] that forms the plaques in the brain that are the hallmark of Alzheimer’s,” the AP story reported.

AP also reported that Japanese scientists at the AAIC presented results of a validation test conducted on 201 people who had either Alzheimer’s, other types of dementia, or little or no symptoms. They found that the test “correctly identified 92% of people who had Alzheimer’s and correctly ruled out 85% who did not have it, for an overall accuracy of 88%.”

Akinori Nakamura, MD, PhD, of the National Center for Geriatrics and Gerontology in Obu, Japan, was a member of the research team and first author of the research paper. He told the AP that the test results “closely matched those from the top tests used now—three types of brain scans and a mental assessment exam.”

Eric McDade, DO (above), Associate Professor of Neurology at Washington University in St. Louis, told Neurology Today, “The results reported here provide a relatively high level of confidence given that this is a relatively well characterized population with an amyloid PET scan to provide confirmation of a significant level of amyloid plaque burden in the brain.” Could this level of physician confidence lead to a clinical laboratory test based on the plasma biomarker? (Photo copyright: Washington University.)

Koichi Tanaka is a Japanese engineer who won the Nobel prize winner for chemistry. He heads the Koichi Tanaka Research Lab at Shimadzu Corp. (OTCMKTS:SHMZF) in Kyoto, Japan, and was on the team that developed the Amyloid beta biomarker test that was presented at AAIC. He told Bloomberg, “Our finding overturned the common belief that it wouldn’t be possible to estimate amyloid accumulation in the brain from blood. We’re now being chased by others, and the competition is intensifying.”

But Tanaka cautions that the test needs further study before it is ready for clinical use, and that for now “it belongs in the hands of drug developers and research laboratories,” Bloomberg reported.

Other Studies into Developing an Alzheimer’s Biomarker

Alzheimer’s is usually diagnosed after symptoms appear, such as memory loss. To arrive at their diagnoses, doctors often rely on medical history, brain imaging (MRI, CT), PET, and measurement of amyloid in spinal fluid.  

An article published on Alzforum, a website and news service dedicated to the research and treatment for Alzheimer’s and other related disorders, noted a study by King’s College London researchers who, using mass spectrometry, “found a panel of biomarkers that predicted with almost 90% accuracy whether cognitively normal people had a positive amyloid scan.”

Nicholas Ashton, PhD, neuroscientist and Wallenberg Postdoctoral Fellow at University of Gothenburg in Sweden, and first author of the King’s College study, explained that “Amyloid-burden and neurofilament light polypeptide (NFL) peptides were important in predicting Alzheimer’s, but alone they weren’t as predictable as when we combined them with novel proteins related to amyloid PET.”

The researchers published their study earlier this year in Science Advances. “Using an unbiased mass spectrometry approach, we have found and replicated with high accuracy, specificity, and sensitivity a plasma protein classifier reflecting amyloid-beta burden in a cognitively unimpaired cohort,” the researchers wrote.

Meanwhile, researchers at Washington University School of Medicine St. Louis, along with the German Center for Neurodegenerative Diseases, a member of the Helmholtz Association, stated in a news release that a blood test they developed works by detecting leaks of NFL before the onset of symptoms. When the protein is found in cerebrospinal fluid, it could be a sign that Alzheimer’s may develop, as well as point to other neurodegenerative conditions such as multiple sclerosis, brain injury, or stroke, the researchers stated.  

“This is something that would be easy to incorporate into a screening test in a neurology clinic,” Brian Gordon, PhD, Assistant Professor of Radiology at Washington University’s Mallinckrodt Institute of Radiology, and an author of the study, stated in the news release.

These parallel studies into screening for Alzheimer’s by researchers worldwide are intriguing. The favorable results suggest that someday there may be a screen for Alzheimer’s using a clinical laboratory blood test.

With Alzheimer’s affecting nearly six million Americans of all ages, such an assay would enable clinical laboratories to help many people.

—Donna Marie Pocius

Related Information:

Scientists Close in On Blood Test for Alzheimer’s

Advances in the Global Search for Blood Markers for Alzheimer’s Disease and Other Dementias

A Blood Test Can Predict Dementia. Trouble Is, There’s No Cure

Plasma Biomarker for Amyloid Correlates with Alzheimer’s Progression, Study Finds

High Performance Plasma Amyloid-β Biomarkers for Alzheimer’s Disease

Panel Blood Markers Signals Amyloid in Brain

A Plasma Protein Classifier for Predicting Amyloid Burden for Preclinical Alzheimer’s Disease

Blood Test Detects Alzheimer’s Damage Before Symptoms; Test Also May Identify Neurodegeneration in Other Brain Diseases

Blood-Brain Barrier Breakdown is an Early Biomarker of Human Cognitive Dysfunction

Researchers in Two Countries Develop Blood Tests That Detect Alzheimer’s Decades Before Symptoms Appear Could Eventually Give Clinical Laboratories A Diagnostic Tool

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