The NIH’s Researching COVID to Enhance Recovery (RECOVER) Initiative used a cohort study of more than 10,000 individuals with and without previous COVID-19 diagnoses and compared samples using 25 common laboratory tests in hopes a useful biomarker could be identified. They were unsuccessful.
Long COVID—or PASC—is an umbrella term for those with persistent post-COVID infection symptoms that negatively impact quality of life. Though it affects millions worldwide and has been called a major public health burden, the NIH/Langone study scientists noted one glaring problem: PASC is defined differently in the major tests they studied. This makes consistent diagnoses difficult.
The study brought to light possible roadblocks that prevented biomarker identification.
“This study is an important step toward defining long COVID beyond any one individual symptom,” said study author Leora Horwitz, MD (above), director of the Center for Healthcare Innovation and Delivery Science and co-principal investigator for the RECOVER CSC at NYU Langone, in a Langone Health news release. “This definition—which may evolve over time—will serve as a critical foundation for scientific discovery and treatment design.” In the future, clinical laboratories may be tasked with finding combinations of routine and reference tests that, together, enable a more precise and earlier diagnosis of long COVID. (Photo copyright: Yale School of Medicine.)
NIH/Langone Study Details
“The study … examined 25 routinely used and standardized laboratory tests chosen based on availability across institutions, prior literature, and clinical experience. These tests were conducted prospectively in laboratories that are certified by the Clinical Laboratory Improvement Amendments (CLIA). The samples were collected from 10,094 RECOVER-Adult participants, representing a diverse cohort from all over the US,” Inside Precision Medicine reported.
However, the scientists found no clinical laboratory “value” among the 25 tests examined that “reliably indicate previous infection, PASC, or the particular cluster type of PASC,” Inside Precision Medicine noted, adding that “Although some minor differences in the results of specific laboratory tests attempted to differentiate between individuals with and without a history of infection, these findings were generally clinically meaningless.”
“In a cohort study of more than 10,000 participants with and without prior SARS-CoV-2 infection, we found no evidence that any of 25 routine clinical laboratory values provide a reliable biomarker of prior infection, PASC, or the specific type of PASC cluster. … Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC,” the study authors wrote in Annals of Internal Medicine.
In addition to a vague definition of PASC, the NIH/Langone researchers noted a few other potential problems identifying a biomarker from the research.
“Use of only selected biomarkers, choice of comparison groups, if any (people who have recovered from PASC or healthy control participants); duration of symptoms; types of symptoms or phenotypes; and patient population features, such as sex, age, race, vaccination status, comorbidities, and severity of initial infection,” could be a cause for ambiguous results, the scientists wrote.
Future Research
“Understanding the basic biological underpinnings of persistent symptoms after SARS-CoV-2 infection will likely require a rigorous focus on investigations beyond routine clinical laboratory studies (for example, transcriptomics, proteomics, metabolomics) to identify novel biomarkers,” the study authors wrote in Annals of Internal Medicine.
“Our challenge is to discover biomarkers that can help us quickly and accurately diagnose long COVID to ensure people struggling with this disease receive the most appropriate care as soon as possible,” said David Goff, MD, PhD, director of the division of cardiovascular sciences at the NIH’s National Heart, Lung, and Blood Institute, in an NHLBI news release. “Long COVID symptoms can prevent someone from returning to work or school, and may even make everyday tasks a burden, so the ability for rapid diagnosis is key.”
“Approximately one in 20 US adults reported persisting symptoms after COVID-19 in June 2024, with 1.4% reporting significant limitations,” the NIH/Langone scientists wrote in their published study.
Astute clinical laboratory scientists will recognize this as possible future diagnostic testing. There is no shortage of need.
Though not biomarkers per se, these scores for certain genetic traits may someday be used by clinical laboratories to identify individuals’ risk for specific diseases
Can polygenic risk scores (a number that denotes a person’s genetic predisposition for certain traits) do a better job at predicting the likelihood of developing specific diseases, perhaps even before the onset of symptoms? Researchers at the Broad Institute of MIT and Harvard (Broad Institute) believe so, and their study could have implications for clinical laboratories nationwide.
In cooperation with medical centers across the US, the scientists “optimized 10 polygenic scores for use in clinical research as part of a study on how to implement genetic risk prediction for patients,” according to a Broad Institute news release.
The research team “selected, optimized, and validated the tests for 10 common diseases [selected from a total of 23 conditions], including heart disease, breast cancer, and type 2 diabetes. They also calibrated the tests for use in people with non-European ancestries,” the news release notes.
As these markers for genetic risk become better understood they may work their way into clinical practice. This could mean clinical laboratories will have a role in sequencing patients’ DNA to provide physicians with information about the probability of a patient’s elevated genetic risk for certain conditions.
However, the effectiveness of polygenic risk scores has faced challenges among diverse populations, according to the news release, which also noted a need to appropriately guide clinicians in use of the scores.
“With this work, we’ve taken the first steps toward showing the potential strength and power of these scores across a diverse population,” said Niall Lennon, PhD (above), Chief Scientific Officer of Broad Clinical Labs. “We hope in the future this kind of information can be used in preventive medicine to help people take actions that lower their risk of disease.” Clinical laboratories may eventually be tasked with performing DNA sequencing to determine potential genetic risk for certain diseases. (Photo copyright: Broad Institute.)
Polygenic Scores Need to Reflect Diversity
“There have been a lot of ongoing conversations and debates about polygenic risk scores and their utility and applicability in the clinical setting,” said Niall Lennon, PhD, Chair and Chief Scientific Officer of Broad Clinical Labs and first author of the study, in the news release. However, he added, “It was important that we weren’t giving people results that they couldn’t do anything about.”
In the paper, Lennon and colleagues explained polygenic risk scores “aggregate the effects of many genetic risk variants” to identify a person’s genetic predisposition for a certain disease or phenotype.
“But their development and application to clinical care, particularly among ancestrally diverse individuals, present substantial challenges,” they noted. “Clinical use of polygenic risk scores may ultimately prevent disease or enable its detection at earlier, more treatable stages.”
The scientists set a research goal to “optimize polygenic risk scores for a diversity of people.”
While performing the polygenic risk score testing on participants, Broad Clinical Labs focused on 10 conditions—including cardiometabolic diseases and cancer—selected by the research team based on “polygenic risk score performance, medical actionability, and clinical utility,” the Nature Medicine paper explained.
For each condition, the researchers:
Identified “exact spots in the genome that they would analyze to calculate the risk score.”
Used information from the NIH’s All of Us Research Program to “create a model to calibrate a person’s polygenic risk score according to that individual’s genetic ancestry.”
The All of Us program, which aims to collect health information from one million US residents, has three times more people of non-European ancestry than other data sources developing genetic risk scores, HealthDay News reported.
20% of Study Participants Showed High Risk for Disease
To complete their studies, Broad Institute researchers processed a diverse group of eMERGE participants to determine their clinical polygenic risk scores for each of the 10 diseases between July 2022 and August 2023.
Listed below are all conditions studied, as well as the number of participants involved in each study and the number of people with scores indicating high risk of the disease, according to their published paper:
Over 500 people (about 20%) of the 2,500 participants, had high risk for at least one of the 10 targeted diseases, the study found.
Participants in the study self-reported their race/ancestry as follows, according to the paper:
White: 32.8%
Black: 32.8%
Hispanic: 25.4%
Asian: 5%
American Indian: 1.5%
Middle Eastern: 0.9%
No selection: 0.8%
“We can’t fix all biases in the risk scores, but we can make sure that if a person is in a high-risk group for a disease, they’ll get identified as high risk regardless of what their genetic ancestry is,” Lennon said.
Further Studies, Scoring Implications
With 10 tests in hand, Broad Clinical Labs plans to calculate risk scores for all 25,000 people in the eMERGE network. The researchers also aim to conduct follow-up studies to discover what role polygenic risk scores may play in patients’ overall healthcare.
“Ultimately, the network wants to know what it means for a person to receive information that says they’re at high risk for one of these diseases,” Lennon said.
The researchers’ findings about disease risk are likely also relevant to healthcare systems, which want care teams to make earlier, pre-symptomatic diagnosis to keep patients healthy.
Clinical laboratory leaders may want to follow Broad Clinical Labs’ studies as they perform the 10 genetic tests and capture information about what participants may be willing to do—based on risk scores—to lower their risk for deadly diseases.
Researchers note that many sources of errors associated with diagnostic testing involve how providers order tests and how specimens are handled
ECRI (Emergency Care Research Institute), a non-profit organization that focuses on healthcare quality and patient safety, has released results from a study which lays blame for most diagnostic errors on systemic issues that arise during clinical laboratory, radiology, and other diagnostic testing processes. These issues relate to “ordering, collecting, processing, obtaining results, or communicating results,” the organization stated in a news release.
“It’s a common misconception that if a patient has a missed or incorrect diagnosis, their doctor came up with the wrong hypothesis after having all the facts,” said ECRI President and CEO Marcus Schabacker MD, PhD, in the news release. “That does happen occasionally, but we found that was tied to less than 3% of diagnostic errors. What’s more likely to break the diagnostic process are technical, administrative, and communication-related issues. These represent system failures, where many small mistakes lead to one big mistake.”
The researchers based their analysis on reports of adverse patient safety events and “near-misses” submitted to ECRI and the Institute for Safe Medication Practices (ISMP) in 2023. Healthcare providers submitted the data from across the US, ECRI noted.
From a total of 3,014 patient safety events, ECRI determined that 1,011 were related to diagnostic errors. Then, it sorted the events based on “the appropriate step in the diagnostic process where the breakdown occurred,” according to the news release.
ECRI did not reveal how many errors were related to clinical laboratory testing as opposed to radiological or ultrasound imaging.
“The problem of diagnostic safety comes down to the lack of a systems-based approach,” said ECRI President and CEO Marcus Schabacker MD, PhD (above), in a news release. “Since there are multiple potential failure points, a single intervention is insufficient.” Diagnostic errors can also include imaging/radiology and other types of diagnostic procedures—not just clinical laboratory tests. (Photo copyright: ECRI.)
Where Errors Occur
According to ECRI’s analysis, the largest number of errors by far (nearly 70%) happened during the clinical laboratory testing process. Among these, “more than 23% were a result of a technical or processing error, like the misuse of testing equipment, a poorly processed specimen, or a clinician lacking the proper skill to conduct the test,” ECRI stated. “Another 20% of testing errors were a result of mixed-up samples, mislabeled specimens, and tests performed on the wrong patient.”
Outside the testing process, other errors occurred during monitoring and follow-up (12%) and during referral and consultation (9%).
One major factor behind diagnostic errors, ECRI noted, was miscommunication among providers and between providers and patients.
The organization also cited “productivity pressures that prevent providers from exploring all investigative options or from consulting other providers” as leading to diagnostic errors.
In some cases, providers who ordered lab tests delayed reviewing the results or the patients were not notified of the results.
“Referrals to specialists or requests for additional consultations can complicate the process, presenting more potential failure points,” ECRI noted.
Troubling Imaging Anecdotes, Previous Studies
The ECRI news release cites two de-identified patient stories, both related to imaging. One case involved a woman who “experienced abdominal pain and abnormal vaginal bleeding,” but a diagnosis of uterine cancer was delayed nearly a year. “MRIs were ordered, but not all the results were reviewed, as her symptoms worsened. Despite masses being detected on an ultrasound, a missed appointment and communication barriers delayed her diagnosis. She was finally diagnosed after severe pain led to hospitalization.”
In one “near-miss” incident, a patient did not receive an essential carotid ultrasound procedure prior to being scheduled for open-heart surgery. Staff caught the omission and canceled the surgery. A later ultrasound “revealed he would have had a catastrophic surgical outcome if the surgery had proceeded as scheduled,” ECRI stated.
Two earlier studies noted in the news release highlight the impact of diagnostic errors.
A 2017 study, published in the journal BMJ Quality Safety, estimated that diagnostic errors affect approximately 5% of US adults—a total of 12 million—each year. In that paper, the authors combined estimates from three observational studies that defined diagnostic error in similar ways.
“Based upon previous work, we estimate that about half of these errors could potentially be harmful,” the authors wrote.
And a 2024 study published in the same journal estimated that 795,000 Americans die or become permanently disabled each year due to misdiagnosis of dangerous diseases. “Just 15 diseases account for about half of all serious harms, so the problem may be more tractable than previously imagined,” the authors wrote.
Recommendations for Providers, Labs
ECRI advised that healthcare providers should adopt a “total systems safety approach and human-factors engineering” to reduce diagnostic errors. This is good advice for clinical laboratories as well.
Specific steps should include “integrating EHR workflows, optimizing testing processes, tracking results, and establishing multidisciplinary diagnostic management teams to analyze safety events,” the news release states.
Schabacker also advised patients to “ask questions to understand why their doctor is ordering tests, and are those tests urgent,” he said. “Schedule your appointments and tests quickly and follow up with your provider if you’re awaiting results. If possible, ask a family member or friend to join you in important appointments, to help ask questions and take notes.”
Clinical laboratory managers have been alerted to the involvement of lab testing in incidents of medical errors. This report by ECRI is more evidence of the gaps in care delivery that often contribute to medical error. Medical lab professionals may want to review the ECRI report to learn more about what the authors identify as the specific breakdowns in care processes that contribute to medical errors.
Is it possible that there is a connection between an individual’s gut microbiota and the ability to fight off gastrointestinal (GI) cancer? Findings from a preliminary research study performed by researchers in South Korea suggest that a link between the two may exist and that fecal microbiota transplants (FMTs) may enhance the efficacy of immunotherapies for GI cancer patients.
The proof-of-concept clinical trial, conducted at the Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea, analyzed how an FMT could help 13 patients with metastatic solid tumors that were resistant to the anti-PD-1 antibody drug known as nivolumab (Opdivo). Anti-PD-1 drugs are immunotherapies that help treat cancer by improving an individual’s immune response against cancer cells.
Four of the trial participants had gastric cancer, five had esophageal cancer, and the remaining four had hepatocellular carcinoma. The patients were given a colonoscopy to implant the FMTs. The recipients also received antibiotics to reduce the response of their existing microbiotas.
The FMT donors also had gastric cancer, esophageal cancer, or hepatocellular carcinoma. Prior to donating their fecal matter, the donors experienced complete or partial response to the anti-PD-1 drugs nivolumab or pembrolizumab (Keytruda) for at least six months after receiving initial treatments.
“This research highlights the complex interplay between beneficial and detrimental bacteria within the gut microbiota in determining treatment outcomes,” co-senior study author Hansoo Park, MD, PhD, Assistant Professor, Biomedical Science and Engineering, Gwangju Institute of Science and Technology, told The ASCO Post. “While the connection between gut microbiota and immune response to cancer therapy has been a growing area of interest, our study provides concrete evidence and new avenues for improving treatment outcomes in a broader range of cancers,” he added. Further studies may confirm the need for microbiome testing by clinical laboratories to guide clinicians treating patients with colon cancers. (Photo copyright: Gwangju Institute of Science and Technology.)
Surprising Results
Fecal material for an FMT procedure combines donated fecal matter with a sterile saline solution which is then filtered to produce a liquid solution. That solution is then administered to the recipient via colonoscopy, upper GI endoscopy, enema, or an oral capsule. The solution may also be frozen for later use.
Upon analyzing the recipients, the scientists found that six of the patients (46.2%) who had experienced resistance to immunotherapies for their cancers, benefitted from the FMTs.
“Both donors were long-lasting, good responders to anti-PD-1 inhibitors, but because we did not yet know the causative bacteria responsible for the [FMT] response, we could not predict whether the treatment would be effective,” she added.
The researchers also determined that the presence of a bacterial strain known as Prevotella merdae helped to improve the effectiveness of the FMTs, while two strains of bacteria—Lactobacillus salivarius and Bacteroides plebeius (aka, Phocaeicola plebeius)—had a detrimental impact on the transplants.
Challenges to Widespread Adoption of FMTs
The researchers acknowledge there are challenges in widespread acceptance and use of FMTs in treating cancers but remain optimistic about the possibilities.
“Developing efficient and cost-effective methods for production and distribution is necessary for widespread adoption,” Sook Ryun Park told The ASCO Post. “Addressing these challenges through comprehensive research and careful planning will be essential for integrating FMT into the standard of care for cancer treatment.”
More research and clinical trials are needed before this use of FMTs can be utilized in clinical settings. However, the study does demonstrate that the potential benefits of FMTs may improve outcomes in patients with certain cancers. As this happens, microbiologists may gain a new role in analyzing the microbiomes of patients with gastrointestinal cancers.
“By examining the complex interactions within the microbiome, we hope to identify optimal microbial communities that can be used to enhance cancer treatment outcomes,” Hansoo Park told The ASCO Post. “This comprehensive approach will help us understand how the microbial ecosystem as a whole contributes to therapeutic success.”
Discovery could lead to new treatments for cancer and tumors, but probably not to any new diagnostic assays for clinical laboratories
Researchers at the University of Texas Southwestern (UTSW) Medical Center have reported discovery of “acid walls” that appear to protect various types of cancer tumors from attack by the body’s immune system cells. Though the discovery is not directly related to a biomarker for a clinical laboratory diagnostic test, the basic research will help scientists develop ways to address the tumor’s acid wall strategy for defeating the immune system.
The UT scientists made their discovery using an internally developed imaging technique that employs nanoparticle probes to detect levels of acidity in cells. The research, they suggest, “could pave the way for new cancer treatment approaches that alter the acidic environment around tumors,” according to a UTSW press release.
“This study revealed a previously unrecognized polarized extracellular acidity that is prevalent around cancer cells,” said lead study author Jinming Gao, PhD (above), Professor in the Harold C. Simmons Comprehensive Cancer Center and head of the Gao Lab at UT Southwestern Medical Center, in a press release. Gao believes the study “will lead to several new lines of research, such as studies to better understand how cancer cells polarize their acid excretion, how those cells can withstand the acidity level that kills CD8+ T cells, and how to inhibit acid excretion to allow T cells to better kill cancer cells,” the press release notes. (Photo copyright: University of Texas.)
Developing Acid Walls
As explained in the press release, scientists have long known that cancer cells are slightly more acidic than most healthy tissue. Gao and his team designed a nanoparticle known as pegsitacianine—a pH-sensitive fluorescent nanoprobe for image-guided cancer surgery—that disassembles and lights up when exposed to the acidic conditions in tumors.
However, “it was unclear why these nanoparticles fluoresced since a tumor’s acidity was thought to be too mild to trigger their activation,” the press release note.
To learn more, they used nanoparticle probes to illuminate a variety of individual cancer cells sampled from humans and mice, including lung, breast, melanoma, and glioblastoma, as well as tumor tissue. They discovered that the cancer cells secreted lactic acid—a waste product of digested glucose—at higher levels than previously known. The cells “pumped” the acid away from their malignant neighbors to form a protective “acid wall” around the tumor, the researchers noted in Nature Biomedical Engineering.
“Samples from human tumors showed that this acid wall was practically devoid of CD8+ T cells within the tumors, an immune cell type known to fight cancer,” the press release states. “When the researchers grew cancer cells and CD8+ T cells together in petri dishes that had been acidified to a 5.3 pH, the cancer cells were spared while the CD8+ T cells perished within three hours, suggesting that this severe acidity might thwart immune cell attack without harming the cancer cells.”
Gao’s team previously discovered that sodium lactate, the “conjugate base of lactic acid” as they describe it, increases the longevity of T cells and thus enhances their cancer-fighting capabilities. The researchers described the two molecules—lactate and lactic acid—as “Dr. Jekyll and Mr. Hyde,” and suggested that future therapies could seek to convert lactic acid to lactate.
“Gao noted that this discovery will lead to several new lines of research, such as studies to better understand how cancer cells polarize their acid excretion, how those cells can withstand the acidity level that kills CD8+ T cells, and how to inhibit acid excretion to allow T cells to better kill cancer cells,” the press release states.
Commercializing the Technology
Pegsitacianine was designed to aid cancer surgeons by illuminating the edges of solid metastatic tumors in real time during surgery, a 2023 UTSW Medical Center press release explains. About 24 hours prior to surgery, nanoprobes are delivered via IV. Then, the surgeon uses a near-infrared camera to visualize the cells.
UTSW has licensed pegsitacianine to OncoNano Medicine, a Dallas-area biotech startup launched to commercialize technologies from Gao Lab. Gao and his colleague Baran Sumer, MD, Professor and Chief of the Division of Head and Neck Oncology in UT Southwestern Medical Center’s Department of Otolaryngology and co-author on the study, both sit on OncoNano’s advisory board.
In January 2023, OncoNano announced that pegsitacianine had received Breakthrough Therapy Designation for Real-Time Surgical Imaging from the US Food and Drug Administration (FDA), which will fast-track the technology for development and regulatory review.
In a Phase II clinical trial published in the Annals of Surgical Oncology, the researchers tested the technology as part of cytoreductive surgery in patients with peritoneal metastases. However, a November 2023 UTSW press release noted that the technology is “tumor-agnostic and could potentially be used in other forms of cancer.” It is currently ready for Phase 3 trials, according to the OncoNano website.
More research and studies are needed to better understand this dynamic of cancer cells. Collectively, this research into cancer by different scientific teams is adding new insights into the way tumors originate and spread. At this time, these insights are not expected to lead to any new diagnostics tests that pathologists and clinical laboratories could use to detect cancer.
