New clinical laboratory test could replace conventional spinal tap for diagnosing neurodegenerative disease
In a proof-of-concept study, University of Pittsburgh (Pitt) scientists validated a clinical laboratory test that measures more than 100 different genetic sequences associated with Alzheimer’s disease. The Pitt researchers believe the new diagnostic platform could help clinicians “capture the multifaceted nature of Alzheimer’s pathology and streamline early disease diagnostics,” according to a news release.
Clinical laboratory blood tests that detect biomarkers such as phosphorylated tau protein (pTau) have emerged in studies as diagnostic possibilities for Alzheimer’s disease, which is traditionally diagnosed using a lumbar puncture (spinal tap) procedure.
In their paper, neuroscientist Thomas Karikari, PhD, Assistant Professor of Psychiatry at University of Pittsburgh, lead author of the study, and his research team acknowledged that progress has been made in detecting Alzheimer’s disease with blood-based biomarkers. However, they note that “two key obstacles remain: the lack of methods for multi-analyte assessments and the need for biomarkers for related pathophysiological processes like neuroinflammation, vascular, and synaptic dysfunction.”
The Pitt scientists believe the focus on so-called “classical Alzheimer’s blood biomarkers” limits exploration of neurodegenerative disease.
“Alzheimer’s disease should not be looked at through one single lens. Capturing aspects of Alzheimer’s pathology in a panel of clinically validated biomarkers would increase the likelihood of stopping the disease before any cognitive symptoms emerge,” said neuroscientist Thomas Karikari, PhD (above), Assistant Professor of Psychiatry, University of Pittsburgh, and lead author of the study in a news release. Should further studies prove Pitt’s research sound, clinical laboratories may have a replacement test for diagnosing neurodegenerative disease. (Photo copyright: University of Pittsburgh.)
On its website, Alamar Biosciences explains that the disease panel offers neurological researchers:
“Multiplexed analysis of 120 neuro-specific and inflammatory proteins from 10 µl of plasma or CSF (cerebrospinal fluid).
Detection of “critical biomarkers—including pTau-217, GFAP (glial fibrillary acidic protein), NEFL (neurofilament light polypeptide) and alpha-synuclein.”
The NULISAseq test works with “a proprietary sequential immunocomplex capture and release mechanism and the latest advances in next-generation sequencing,” according to the company.
Inside Precision Medicine noted that the Alamar Biosciences assay enabled Pitt scientists to detect:
Biomarkers (usually found in CSF) “correlating with patients’ amyloid positivity status and changes in amyloid burden over time,” and,
Biomarkers including “neuroinflammation, synaptic function, and vascular health, which had not previously been validated in blood samples.”
“The performance of the NULISA platform was independently validated against conventional assays for classic Alzheimer’s biomarkers for each sample. Biomarker profiles over two years were also compared with imaging-based measures of amyloid, tau, and neurodegeneration,” LabMedica reported.
Opportunity to Track Alzheimer’s
Karikari sees the diagnostic platform being used to track individuals’ blood biomarker changes over time.
In their Molecular Neurodegeneration paper, the Pitt researchers wrote, “These (results) were not limited to markers such as pTau217, p-Tau231, p-Tau181, and GFAP, the elevation of which have consistently shown strong associations with brain Aβ [amyloid beta] and/or tau load, but included novel protein targets that inform about the disease state of the individual in different pathological stages across the biological Alzheimer’s disease continuum.”
About seven million Americans are affected by Alzheimer’s disease, according to the Alzheimer’s Association, which estimated that figure will grow to 13 billion by 2050.
Further studies by Karikari may include larger samples and greater diversity among the people studied, Inside Precision Medicine noted.
“[Karikari’s] lab is developing a predictive model that correlates biomarker changes detected using NULISAseq with brain autopsy data and cognitive assessments collected over the course of several years. Their goal is to identify blood biomarkers that can help stage the disease and predict its progression, both for decision-making around clinical management and treatment plans,” the Pitt news release states.
The Pitt scientists have developed a multiplex test that works with 100 different genetic sequences associated with Alzheimer’s. Such advances in the understanding of the human genome are giving scientists the opportunity to combine newly identified gene sequences that have a role in specific disease states.
In turn, as further studies validate the value of these biomarkers for diagnosing disease and guiding treatment decisions, clinical laboratories will have new assays that deliver more value to referring physicians and their patients.
Small handheld device uses sound waves to detect certain clinical laboratory biomarkers in blood samples
University of Colorado Boulder researchers have developed a novel technology that uses sound waves to test for biomarkers in blood samples. In addition to being very easy to use, the handheld device is portable, highly sensitive, and delivers results in minutes. Though not ready for clinical use, this is yet another example of how researchers are developing faster diagnostic tests that can be performed in near-patient settings, and which do not have to be done in core laboratories, shortening time to answer.
The small instrument—referred to as an “acoustic pipette”—delivers sound waves to tiny particles within the device called “functional negative acoustic contrast particles” (fNACPs). These particles are cell-sized balls that can be customized with different coatings to identify specific biomarkers—such as viruses or proteins—in tiny blood samples, according to a news release.
To operate the device, the custom fNACPs are mixed with a drop of blood and then placed inside the acoustic pipette. The mixture is then blasted with sound waves, which forces particles carrying certain biomarkers to one side of the chamber where they are trapped while the rest of the blood is expelled. The captured biomarkers are then labeled with fluorescent tags and examined with lasers to determine how much of a specific biomarker is present.
“We’re basically using sound waves to manipulate particles to rapidly isolate them from a really small volume of fluid,” said Cooper Thome (above), PhD candidate in Chemical and Biological Engineering at UC Boulder and first author of the study in a news release. “It’s a whole new way of measuring blood biomarkers,” he added. Should further studies validate this approach, clinical laboratories may be able to use this technology to perform diagnostic tests with smaller volumes of patient samples. (Photo copyright: University of Colorado Boulder.)
Blood Testing Quickly and in Multiple Settings
To test their invention, the UC Boulder researchers examined antibodies against a protein called ovalbumin, which is found in egg whites and often used in the development of various vaccines. The scientists discovered that their device could detect the antibodies even in low amounts.
Current rapid tests known as lateral-flow assays can detect specific biomarkers in blood or urine samples but cannot determine how much of the biomarker is present. Enzyme-linked immunotherapy assays (ELISA), the leading clinical laboratory blood test, requires expensive equipment and can take hours to days for results to be received.
With UC Boulder’s new handheld device, tiny blood samples collected from a single finger prick could ensure accurate test results are available quickly at the point of care as well as outside of traditional healthcare settings. This would greatly benefit people in developing nations and underserved communities and may help ease test anxiety for individuals who are apprehensive about traditional blood tests.
“We’ve developed a technology that is very user friendly, can be deployed in various settings, and provides valuable diagnostic information in a short time frame,” said Wyatt Shields IV, PhD, Assistant Professor, Department of Chemical and Biological Engineering, UC Boulder, and senior author of the research in the news release.
“In our paper, we demonstrate that this pipette and particle system can offer the same sensitivity and specificity as a gold-standard clinical test can but within an instrument which radically simplifies workflows,” he added. “It gives us the potential to perform blood diagnostics right at the patient’s bedside.”
The graphic above, taken from UC Boulder’s published paper, illustrates how “fNACPs capture target biomarkers from whole blood samples. fNACPs are purified from blood components by acoustic trapping and captured biomarkers are labeled with a fluorescent antibody within the acoustic pipette. fNACP fluorescence is then measured to determine biomarker presence and concentration.” (Graphic/caption copyright: University of Colorado Boulder.)
Not Like Theranos
The authors of the UC Boulder study are cognizant of some skepticism surrounding the field of biosensing, especially after the downfall of Theranos. The scientists insist their technology is different and based on systematic experiments and peer-reviewed research.
“While what they (Theranos) claimed to do isn’t possible right now, a lot of researchers are hoping something similar will be possible one day,” said Thome in the news release. “This work could be a step toward that goal—but one that is backed by science that anybody can access.”
The device is still in its initial proof-of-concept stage, but the UC Boulder scientists have applied for patents for the apparatus and are searching for ways to scale its use and expand its capabilities.
“We think this has a lot of potential to address some of the longstanding challenges that have come from having to take a blood sample from a patient, haul it off to a lab, and wait to get results back,” Shields noted.
More research, studies, and regulatory reviews will be needed before this technology becomes available for regular, widespread use. But UC Boulder’s new blood testing device is another example of a research team using novel technology to test for known biomarkers in ways that could improve standard clinical laboratory testing.
Clinical laboratory executives and pathology leaders may want to develop strategies for supporting the growing numbers of at-home screening and diagnostic test users
Findings of a national poll conducted by the University of Michigan (U-M) exploring consumers’ purchases suggests seniors are becoming more comfortable with ordering and using at-home medical testing. Their choice of tests and opinions may be of interest to clinical laboratory executives, pathologists, and primary care physicians considering programs to support self-test purchasers.
The researchers found that 48% of adults, ages 50 to 80, purchased at least one at-home medical test, and that 91% of the buyers indicated intentions to purchase another test in the future, according to a U-M news release.
In their paper, they note that “validity, reliability, and utility of at-home tests is often uncertain.” Further, understanding and responding to test results—especially since caregivers may not have ordered them—could lead to “a range of unintended consequences,” they wrote.
“As a primary care doctor, I would want to know why my patient chose to take an at-home test that I didn’t order for them. We also need to understand in greater detail why folks use at-home tests instead of traditional means, beyond convenience,” said the U-M study’s lead author Joshua Rager, MD, a research scientist at William M. Tierney Center for Health Services Research at Regenstrief Institute, who is now an assistant professor of medicine, Indiana University, in a news release. The findings of the U-M study will be of interest to clinical laboratory executives and pathology leaders. (Photo copyright: Regenstrief Institute.)
Free COVID-19 Tests Ignite At-Home Testing
In their Journal of Health Care paper, the U-M researchers speculate that curiosity in at-home testing may have been propelled by the offer of free COVID-19 tests by the US government starting in 2021 during the pandemic.
They also noted the different ways at-home test kits are performed by healthcare consumers. Some, such as COVID-19 rapid antigen tests, return results to users in a few moments similar to pregnancy tests. Others involve self-collecting specimens, such as a stool sample, then sending the specimen to a clinical laboratory for analysis and results reporting to physicians.
Of those older adults who participated in U-M’s National Poll on Healthy Aging study, the following bought at-home medical tests online or from pharmacies and supermarkets, according to U-M’s paper:
As to perceptions of at-home medical testing by users, when polled on their test experience, the surveyed seniors reported the following:
75.1% perceived at-home medical tests to be more convenient than conventional medical tests.
59.9% believe the tests “can be trusted to give reliable results.”
54.8% believe the tests “are regulated by government.”
66% called them a “good value.”
93.6% indicated results “should be discussed with my doctor.”
Inconsistency in how people shared test results with their healthcare providers was a concern voiced by the researchers.
“While nearly all patients who had bought an at-home cancer screening test shared the results with their primary care provider, only about half of those who tested for an infection other than COVID-19 had. This could have important clinical implications,” the researchers wrote in their paper.
Confusion over Government Regulation
The U-M study also revealed consumer misunderstanding about government regulation of at-home clinical laboratory tests purchased over-the-counter.
The US Food and Drug Administration (FDA) cleared “some diagnostic at-home tests for over-the counter use. But many tests on the market are unregulated or under-regulated,” the authors wrote, adding, “Our results suggest, however, that patients generally believe at-home tests are regulated by government, but a substantial minority did not, which may reflect public confusion in how at-home testing is regulated.”
Women, College-Educated Buy More At-Home Tests
Purchase of at-home tests varies among groups, as follows, the news release noted:
56% and 61% of older adults with a college degree or household income above $100,000, respectively, were “much more likely” to buy at-home tests than people in other income and education brackets.
87% of women would buy at-home tests again compared with 76% of men.
89% of college-educated people would purchase the tests again, compared with 78% of people with high school educations or less.
Future U-M research may explore consumers’ awareness/understanding concerning federal regulations of at-home testing, Rager noted.
“At-home tests could be used to address disparities in access to care. We hope these findings will inform regulators and policymakers and spark future research on this topic,” he said in the news release.
The U-M Institute for Healthcare Policy and Innovation survey results confirm that the country’s senior generations are becoming comfortable with at-home and self-testing options. As Dark Daily has previously suggested, clinical laboratories may want to develop service offerings and a strategy for supporting patients who want to perform their own lab tests at home.
“Previously … CDC developed tests for emerging pathogens and then shared those tests with others, and then after that, commercial labs would develop their own tests,” Shah told CNN. “That process took time. Now with these new arrangements, commercial labs will be developing new tests for public health responses alongside CDC, not after CDC.”
In a news release announcing the contract, ARUP Laboratories also characterized the move as a shift for the agency.
“The new contract formalizes ARUP’s relationship with the CDC,” said Benjamin Bradley, MD, PhD, medical director of the ARUP Institute for Research and Innovation in Infectious Disease Genomic Technologies, High Consequence Pathogen Response, Virology, and Molecular Infectious Diseases. “We continue to expand our capabilities to address public health crises and are prepared to scale up testing for H5N1, or develop other tests quickly, should the need arise.”
“To be clear, we have no evidence so far that this [bird flu] virus can easily infect human beings or that it can spread between human beings easily in a sustained fashion,” Jennifer Nuzzo, DrPH (above), Director of the Pandemic Center and Professor of Epidemiology at Brown University School of Public Health, told CNN. “If it did have those abilities, we would be in a pandemic.” Clinical laboratory leaders will recall the challenges at the CDC as it developed its SARS-CoV-2 test early in the COVID-19 pandemic. (Photo copyright: Brown University.)
Missouri Case Raises Concerns
The first human infection of HPAI was reported in late March following a farmer’s “exposure to dairy cows presumably infected with bird flu,” the CDC stated in its June 3, 2024, bird flu Situation Summary. That followed confirmation by the USDA’s Animal and Plant Health Inspection Service (APHIS) of an HPAI outbreak in commercial poultry flocks in February 2022, and the CDC’s confirmation of the first known infections in dairy herds reported on March 25, 2024.
Concerns about the outbreak were heightened in September following news that a person in Missouri had been infected with the virus despite having no known contact with infected animals. CNN reported that it was the 14th human case in the US this year, but all previous cases were in farm workers known to be exposed to infected dairy cattle or poultry.
In a news release, the Missouri Department of Health and Senior Services (DHSS) revealed that the patient, who was not identified, was hospitalized on Aug. 22. This person had “underlying medical conditions,” DHSS reported, and has since recovered and was sent home. Both DHSS and the CDC conducted tests to determine that the virus was the H5 subtype, the news release states.
At present, the CDC states that the public health risk from the virus is low. However, public health experts are concerned that risks could rise as the weather gets cooler, creating opportunities for the virus to mutate “since both cows and other flu viruses will be on the move,” CNN reported.
Concerns over CDC Testing and FDA Oversight
In the months immediately following the first human case of the bird flu virus, Nuzzo was among several public health experts sounding an alarm about the country’s ability to ramp up testing in the face of new pathogens.
“We’re flying blind,” she told KFF Health News in June, due to an inability to track infections in farmworkers. At that time, tests had been distributed to approximately 100 public health labs, but Nuzzo and other experts noted that doctors typically order tests from commercial laboratories and universities.
KFF reported that one diagnostics company, Neelyx Labs, ran into obstacles as it tried to license the CDC’s bird flu test. Founder, CEO, and lead scientist Shyam Saladi, PhD, told KFF that the federal agency had promised to cooperate by facilitating a license and a “right to reference” CDC data when applying for FDA authorization but was slow to come through.
While acknowledging the need for testing accuracy, Greninger contended that the CDC was prioritizing caution over speed, as it did in the early days of the COVID-19 pandemic. “The CDC should be trying to open this up to labs with national reach and a good reputation,” he told KFF.
Another problem, KFF reported, related to the FDA’s new oversight of laboratory developed tests (LDTs), which is causing labs to move cautiously in developing their own tests.
Jennifer Nuzzo, DrPH (above), Director of the Pandemic Center and Professor of Epidemiology at the Brown University School of Public Health co-authored a June 2024 analysis in Health Affairs that called on the CDC to develop “a better testing playbook for biological emergencies.” The authors’ analysis cited earlier problems with the responses to the COVID-19 and mpox (formerly known as monkeypox) outbreaks.
If global surveillance networks have detected a novel pathogen, the authors advise, the US should gather information and “begin examining the existing testing landscape” within the first 48 hours.
Once the pathogen is detected in the US, they continued, FDA-authorized tests should be distributed to public health laboratories and the CDC’s Laboratory Response Network (LRN) laboratories within 48 hours.
Advocates of this approach suggest that within the first week diagnostics manufacturers should begin developing their own tests and the federal government should begin working with commercial labs. Then, within the first month, commercial laboratories should be using FDA-authorized tests to provide “high throughput capacity.”
This may be good advice. Experts in the clinical laboratory and healthcare professions believe there needs to be improvement in how novel tests are developed and made available as novel infectious agents are identified.
Patients outside the US wait even longer to see healthcare specialists with some appointments scheduled a year out in the Canadian province of Nova Scotia
Data recently released by healthcare consulting firm ECG Management Consultants (ECG) reveals that patients in the United States wait an average of 38 days for healthcare appointments. That figure is a significant stretch from the desired industry standard of 14-day or less wait times, according to Becker’s Hospital Review.
Clinical laboratories serve the needs of physicians who see patients and refer testing needed by patients to labs. Thus, average wait times should be of interest to lab professionals who strive to meet reporting turnaround times for lab test results, particularly given the unique way that ECG conducted its survey of patient wait times.
In “The Waiting Game: New-Patient Appointment Access for US Physicians,” ECG wrote, “Adopting a ‘secret shopper’ approach, we put ourselves in the shoes of the average patient trying to book an appointment. We contacted nearly 4,000 physician practices in 23 major cities across the US, posing as a new, commercially insured patient seeking care for general, nonemergent conditions that typically don’t require a physician referral.”
ECG’s study provides “a realistic view of where and in what specialties patients face the most significant challenges to accessing routine care,” the authors wrote in their published report. The report also includes patients’ appointment-keeping behavior based on length of wait times.
“Consumer expectations have evolved significantly in all industries. From buying a plane ticket to making a restaurant reservation, the consumer experience has been highly optimized and customers in turn have become accustomed to information and services being available at their fingertips. They bring the same expectations about speed and convenience to healthcare,” the researchers explained.
ECG pointed out that when patients are required to wait 14 days or more to see their physicians, no shows and cancellations increase dramatically.
“Numerous studies have shown that patients are significantly less likely to show up for appointments that are scheduled further out,” the study authors noted.
“One of the takeaways was how difficult the patient experience is. Not only did our secret shoppers have to go out and find physicians, they had to sit on the phone sometimes on very long holds and go through multiple barriers and jump through hoops,” Jennifer Moody (above), partner with ECG Management Consultants and one of the authors of the study, told Becker’s Hospital Review. “Even in that case, they weren’t successful in scheduling appointments with all the practices they called. I think of the average consumer who might be having a similar experience,” she added. Lengthy wait times are not believed to be an issue when patients need clinical laboratory tests. (Photo copyright: ECG Management Consultants.)
Getting Authentic Results
To gather the study data, ECG distributed its secret shoppers throughout 23 major US cities, reaching almost 4,000 physician practices (between 145-168 per city) to schedule appointments for non-emergency conditions not needing a physical referral.
The researchers gathered wait times for TNAAs (third next available appointments), a common metric. They chose TNAAs because first and second appointments often produce unclear results due to extenuating circumstances or late cancellations, Becker’s Hospital Review reported.
The researchers recorded TNAAs for the following specialties:
Cardiology (39 days),
Dermatology (40 days),
Family medicine (29 days),
Gastroenterology (48 days),
General surgery (22 days),
Neurology (63 days),
Obstetrics/gynecology (37 days),
Ophthalmology (37 days),
Orthopedic surgery (20 days),
Pediatrics (24 days), and,
Rheumatology (68 days).
They found the average wait time to be 38 days. And “of the 253 metropolitan market and specialty combinations included in this research, only 6% had an average wait time of 14 days or less,” Becker’s reported.
The researchers omitted the physician practices that were unable to either take or return calls, take messages, or provide a hold time under five minutes to give the secret shopper an answer, Becker’s added.
Jennifer Moody, Partner, ECG Management Consultants, one of the authors of the study, “was particularly surprised by the portion of callers who never even made it to the stage of learning about wait times. Out of 3,712 physician practices, callers were able to secure responses from only 3,079, meaning nearly one in five physician practices could not provide appointment availability information,” Becker’s reported.
The lowest average wait time in all specialties was 27 days in Houston, and the longest was 70 days in Boston. “A key takeaway from the report is that physician concentration does not guarantee timely access, as a major healthcare hub like Boston helps illustrate,” Becker’s noted, adding that physicians in such areas may “devote time to teaching or research over appointments.”
The graphic above, taken from ECG’s published report, shows the average TNAA times recorded by their secret shoppers at medical specialty practices in major cities across the US. (Graphic copyright: ECG Management Consultants.)
Other Country’s Wait Times
Healthcare systems outside the US struggle with patient wait times as well. Forbes reported that patients of Canada’s public health system “faced a median wait of 27.7 weeks for medically necessary treatment from a specialist after being referred by a general practitioner. That’s over six months—the longest ever recorded.”
Patients in Nova Scotia wait even longer. There they “face a median wait of 56.7 weeks—more than a year—for specialist treatment following referral by a general practitioner. Those on Prince Edward Island are also in the year-long waiting club—a median of just over 55 weeks,” Forbes noted.
And in the UK, a recent survey found that “more than 150,000 patients had to wait a day in A&E [accident and emergency] before getting a hospital bed last year, according to new data,” with the majority of those patients over the age of 65, according to The Guardian.
ECG suggestions that may reduce wait times include:
Adopt automation and self-service tools in an “easily navigable platform” that enables patients to schedule appointments 24/7.
Ensure healthcare providers are “utilized appropriately and at the top of their license.”
Address inequities in access to healthcare regardless of patients’ location or socioeconomic status.
There is more in the ECG report that hospitals—as well as clinical laboratories—can use to reduce patient wait times to see care providers. As the authors wrote, “For patients, the first step of the care journey shouldn’t be the hardest.”
New technique could allow emergency responders to determine severity of LVO stroke while patient is still in the ambulance
Researchers at Brigham and Women’s Hospital in Massachusetts say they have developed a clinical laboratory test that can quickly determine whether a patient is experiencing one of the deadliest types of strokes, known as an ischemiclarge vessel occlusion (LVO) stroke. The development team believes this new assay could be deployed as a point-of-care test to enable faster diagnosis of stroke events.
The test combines measurement of two blood plasma biomarkers with an established clinical score used by clinicians and EMS personnel to assess stroke severity. Compared with current approaches, their technique more accurately differentiates LVO strokes from other types of strokes, making it more likely that patients receive appropriate treatment in a timely manner, the researchers said in a Brigham news release.
Dark Daily has long predicted that advances in technology and computing power would make it possible for pathologists and clinical laboratory scientists to combine multiple established biomarkers (individually not associated with the disease state targeted) with other clinical and patient data to create the ability to make an accurate and earlier diagnosis.
Ultimately, Brigham’s research could “aid in the development of a point‐of‐care diagnostic test capable of guiding prehospital LVO stroke triage,” wrote Joshua Bernstock, MD, PhD, Clinical Fellow in Neurosurgery at Brigham and Women’s Hospital, lead author of the study, and colleagues.
“We have developed a game-changing, accessible tool that could help ensure that more people suffering from stroke are in the right place at the right time to receive critical, life-restoring care,” said Joshua Bernstock, MD, PhD (above), Clinical Fellow in Neurosurgery at Brigham and Women’s Hospital and lead author of the Brigham study that developed the clinical laboratory test that the researchers say can enable emergency caregivers to determine quickly and accurately if a patient is having an ischemic large vessel occlusion (LVO) stroke. (Photo copyright: Brigham and Women’s Hospital.)
Early Identification of LVO Stroke
As explained in the news release, an LVO stroke is a type of ischemic stroke caused by obstruction in a major brain artery. The researchers noted that LVO strokes account for “62% of poststroke disabilities and 96% of poststroke death.”
These strokes are readily treatable using endovascular thrombectomy (EVT), in which the blockages are surgically removed, the news release note. However, the researchers observed that EVT “requires specialized teams and equipment, limiting its availability to comprehensive stroke centers and other EVT‐capable centers.”
This can lead to delays as patients are transferred to those facilities, worsening outcomes and increasing the risk of death, the researchers wrote in Stroke: Vascular and Interventional Neurology. So, early identification of LVO stroke is key to ensuring patients receive timely treatment.
Identifying False Negatives/Positives
One challenge, the news release notes, is that brain bleeds (hemorrhagic stroke) can present similar symptoms, yet require “vastly different” treatment.
“A growing body of work has, therefore, evaluated prehospital stroke assessment scales in an effort to identify LVO strokes in the field,” the researchers wrote. “However, such severity scales lack the sensitivity and specificity required for triaging LVO patients with confidence, resulting in false negatives in patients with LVO as well as false positives in patients with stroke mimics or hemorrhagic stroke.”
As explained by EMS Aware, these assessment scales, such as FAST-ED (field assessment stroke triage for emergency destination) and RACE (rapid arterial occlusion evaluation), attempt to determine the severity of a stroke by assigning scores based on symptoms such as facial palsy, arm weakness, and speech difficulties.
To develop their test, Bernstock and colleagues proposed combining the scales with measurement of two blood proteins:
In their study, they attempted to validate cutoff values for the biomarkers and scales.
To do so, the researchers analyzed data from 323 patients admitted to a Florida hospital with suspected stroke between May 2021 and August 2022. Each was assigned to one of four diagnostic categories based on clinical data from their medical records, which included results of computed tomography (CT scan) or magnetic resonance angiography (MRA). The diagnostic categories included:
The patients were assessed using five stroke severity scales. The researchers used frozen blood samples from the patients to measure the biomarkers. They then used this data to determine the likelihood of LVO stroke and compared the results with the diagnoses as determined by the clinical data.
“Combinations of the blood biomarkers with the scales FAST‐ED or RACE showed the best performance for LVO detection, with a specificity of 94% (for either scale combination) and a sensitivity of 71% for both scales,” the researchers wrote.
Sensitivity was higher in patients who presented within the first six hours from onset of symptoms.
“Critically, application of the biomarker and stroke scale algorithms ruled out all patients with hemorrhage,” the researchers wrote. However, they also suggested that their algorithm could be adjusted to enable early identification of hemorrhagic stroke.
The researchers noted that they chose biomarker cutoffs to maximize specificity, so “a certain number of LVOs are missed. However, as such patients default into ‘standard‐of‐care’ triaging pathways, such a decision is unlikely to represent much clinical risk.”
Testing in the Field
The Brigham researchers used established biological biomarkers combined with modern computing—in combination with the scores from a field assessment test—to develop their new clinical laboratory test that identifies the type of stroke.
Their next step is to carry out “another prospective trial to measure the test’s performance when used in an ambulance,” the news release states. “They have also designed an interventional trial that leverages the technology to expedite the triage of stroke patients by having them bypass standard imaging and move directly to intervention.”
“In stroke care, time is brain,” Bernstock said. “The sooner a patient is put on the right care pathway, the better they are going to do. Whether that means ruling out bleeds or ruling in something that needs an intervention, being able to do this in a prehospital setting with the technology that we built is going to be truly transformative.”
More research and clinical studies are needed. However, the fact that the Brigham team wants to deploy this approach in ambulances is an indication that there is high clinical value from this approach.
Clinical pathologists and medical laboratory managers will want to watch the ongoing development and deployment of this new assay, whether it is run in near-patient settings or core clinical laboratories in support of patients presenting in emergency departments.
