Development of the Critical Values system redefined what STAT means in clinical laboratory testing turnaround times
Where did the concept of critical values and having clinical laboratories report them to referring physicians originate? How did the concept blossom into a standard practice in laboratory medicine? Given the importance of critical values, a lookback into how this aspect of laboratory medicine was developed is helpful to understand how and why this has become an essential element in the practice of medicine and an opportunity for labs to add value in patient care.
According to Stanford Medicine, critical/panic values are defined as “values that are outside the normal range to a degree that may constitute an immediate health risk to the individual or require immediate action on the part of the ordering physician.”
What you’ll read below is an insider’s account of the “birth of critical values reporting.”
According to Lundberg, an unaccompanied man was brought to the hospital in a coma and an examination revealed a laceration to his scalp. The patient was admitted to the neurosurgical unit where clinical laboratory tests were performed, including a complete blood count (CBC) analysis, urinalysis, and serum electrolytes. All the test results came back normal except the patient’s serum glucose (blood sugar level) which was 6 mg% in concentration.
“The hard-copy laboratory results were returned to the ward of origin within two hours of receipt of the specimens in the laboratory. However, the results were not noticed by the house officers who were busy with several other seriously ill patients. Ward personnel also failed to communicate the lab results to the responsible physicians,” Lundberg wrote.
When hospital staff did finally notice the test result the next morning glucose was immediately administered to the patient, but it was too late to prevent irreversible brain damage. The man soon passed away.
Following this incident, the hospital developed a “Critical Value Recognition and Reporting System.” The system generated new numbers that were termed “Panic Values.”
However, “critics complained that good doctors should never panic, so the name was changed to Critical Values,” Lundberg explained.
When any of these critical test values were out of the norm, “we required the responsible laboratory person to quickly verify the result and use the telephone (long before laboratory computers) to personally notify a responsible individual (no messages left) who agreed to find a physician who could quickly act on the result. All was documented with times and names,” he wrote.
“We understand that when a physician wants something, he/she wants it, no matter what. Well, in this patient-focused approach, the physician cannot have it, except as offered by the patient-focused approach, based on TAT [turnaround times of clinical laboratory tests],” wrote George Lundberg, MD (above), President and Chair of the Board of Directors of the Lundberg Institute, and Clinical Professor of Pathology at Northwestern University in an article he penned for the National Medical Journal of India (Photo copyright: Dark Intelligence Group. Shows Dr. Lundberg in 2011 addressing the Executive War College on Diagnostics, Clinical Laboratory, and Pathology Management.)
New Clinical Laboratory Standards
Recognition of the urgency to adopt new hospital standards related to certain clinical laboratory test results came swiftly. In 1972, Lundberg was invited to publish an article explaining the new Critical Value Recognition and Reporting System in Medical Laboratory Observer.
According to Lundberg, “most laboratory tests that are done do not need to be done; the results are either negative, normal, or show no change from a prior result. But some are crucial.”
The original set of Critical Values included the following testing results:
The list of values were later expanded to include “vital values.” These values describe lab results for which “action” is important, but where timing is less urgent. Examples of vital values include:
Lundberg and his colleagues went on to redefine what constitutes a laboratory test and what renders a test successful. They discussed laboratory procedures with committees of clinicians, lab personnel and patients, and reorganized hematology, chemistry, and toxicology based on the turnaround time (TAT) of tests.
“We ‘started the clock’—any and all days/times 24×7—when a specimen arrived at some place within the laboratory, and stopped the clock when a final result was available somewhere in the laboratory,” Lundberg wrote in NMJI. “We categorized all tests as: less than one hour, less than four hours, less than 24 hours, and more than 24 hours, guaranteed, 24×7. As a trade-off, we abolished the concept of ‘STAT’ orders … NO EXCEPTIONS. The rationale of each TAT was the speed with which a result was needed to render proper medical care that mattered to the welfare of the patient, and, of course, that was technically possible.”
Since then, very little has changed for the Critical Values System over the past 50 years. The majority of values added have fallen under the “Vital” category and not the “Critical” category. Today, most health systems and clinical laboratories create their own internal processes and procedures regarding which values need to be reported immediately (critical), which values are not urgent (vital), and how those results should be handled.
Study results from Switzerland come as clinical laboratory scientists seek new ways to tackle the problem of antimicrobial resistance in hospitals
Microbiologists and clinical laboratory scientists engaged in the fight against antibiotic-resistant (aka, antimicrobial resistant) bacteria will be interested in a recent study conducted at the University of Basel and University Hospital Basel in Switzerland. The epidemiologists involved in the study discovered that some of these so-called “superbugs” can remain in the body for as long as nine years continuing to infect the host and others.
The researchers wanted to see how two species of drug-resistant bacteria—K. pneumoniae and E. coli—changed over time in the body, according to a press release from the university. They analyzed samples of the bacteria collected from patients who were admitted to the hospital over a 10-year period, focusing on older individuals with pre-existing conditions. They found that K. pneumoniae persisted for up to 4.5 years (1,704 days) and E. coli persisted for up to nine years (3,376 days).
“These patients not only repeatedly become ill themselves, but they also act as a source of infection for other people—a reservoir for these pathogens,” said Lisandra Aguilar-Bultet, PhD, the study’s lead author, in the press release.
“This is crucial information for choosing a treatment,” explained Sarah Tschudin Sutter, MD, Head of the Division of Infectious Diseases and Hospital Epidemiology, and of the Division of Hospital Epidemiology, who specializes in hospital-acquired infections and drug-resistant pathogens. Sutter led the Basel University study.
“The issue is that when patients have infections with these drug-resistant bacteria, they can still carry that organism in or on their bodies even after treatment,” said epidemiologist Maroya Spalding Walters, MD (above), who leads the Antimicrobial Resistance Team in the Division of Healthcare Quality Promotion at the federal Centers for Disease Control and Prevention (CDC). “They don’t show any signs or symptoms of illness, but they can get infections again, and they can also transmit the bacteria to other people.” Clinical laboratories working with microbiologists on antibiotic resistance will want to follow the research conducted into these deadly pathogens. (Photo copyright: Centers for Disease Control and Prevention.)
COVID-19 Pandemic Increased Antibiotic Resistance
The Basel researchers looked at 76 K. pneumoniae isolates recovered from 19 patients and 284 E. coli isolates taken from 61 patients, all between 2008 and 2018. The study was limited to patients in which the bacterial strains were detected from at least two consecutive screenings on admission to the hospital.
“DNA analysis indicates that the bacteria initially adapt quite quickly to the conditions in the colonized parts of the body, but undergo few genetic changes thereafter,” the Basel University press release states.
The researchers also discovered that some of the samples, including those from different species, had identical mechanisms of drug resistance, suggesting that the bacteria transmitted mobile genetic elements such as plasmids to each other.
One limitation of the study, the authors acknowledged, was that they could not assess the patients’ exposure to antibiotics.
Meanwhile, recent data from the World Health Organization (WHO) suggests that the COVID-19 pandemic might have exacerbated the challenges of antibiotic resistance. Even though COVID-19 is a viral infection, WHO scientists found that high percentages of patients hospitalized with the disease between 2020 and 2023 received antibiotics.
“While only 8% of hospitalized patients with COVID-19 had bacterial co-infections requiring antibiotics, three out of four or some 75% of patients have been treated with antibiotics ‘just in case’ they help,” the WHO stated in a press release.
WHO uses an antibiotic categorization system known as AWaRe (Access, Watch, Reserve) to classify antibiotics based on risk of resistance. The most frequently prescribed antibiotics were in the “Watch” group, indicating that they are “more prone to be a target of antibiotic resistance and thus prioritized as targets of stewardship programs and monitoring.”
“When a patient requires antibiotics, the benefits often outweigh the risks associated with side effects or antibiotic resistance,” said Silvia Bertagnolio, MD, Unit Head in the Antimicrobial resistance (AMR) Division at the WHO in the press release. “However, when they are unnecessary, they offer no benefit while posing risks, and their use contributes to the emergence and spread of antimicrobial resistance.”
Citing research from the National Institutes of Health (NIH), NPR reported that in the US, hospital-acquired antibiotic-resistant infections increased 32% during the pandemic compared with data from just before the outbreak.
“While that number has dropped, it still hasn’t returned to pre-pandemic levels,” NPR noted.
The UPenn researchers have already developed an antimicrobial treatment derived from guava plants that has proved effective in mice, Vox reported. They’ve also trained an AI model to scan the proteomes of extinct organisms.
“The AI identified peptides from the woolly mammoth and the ancient sea cow, among other ancient animals, as promising candidates,” Vox noted. These, too, showed antimicrobial properties in tests on mice.
These findings can be used by clinical laboratories and microbiologists in their work with hospital infection control teams to better identify patients with antibiotic resistant strains of bacteria who, after discharge, may show up at the hospital months or years later.
Clinical laboratories nationwide could follow Yale’s example and enact programs to bring much needed lab services to traditionally underserved communities
Ever since the COVID-19 pandemic drove up demand for telehealth medical services, mobile clinical laboratories have grown in popularity as well, especially among residents of remote and traditionally underserved communities. Now, several divisions of Yale University are getting in on the trend.
“Using a van retrofitted with laboratory-grade diagnostic equipment, the mobile clinic will employ SalivaDirect—a saliva-based COVID-19 PCR test developed at YSPH—to facilitate on-site testing with a turnaround time of two to three hours,” Yale Daily News reported.
Funded by a federal grant, the initial goal was to provide 400 free COVID-19 tests, but the program has exceeded that number. By April 10, the mobile lab had been deployed more than 60 times, appearing at events and pop-up sites throughout various communities in Connecticut, including regular stops at the WHEAT Food Pantry of West Haven.
“[The clinical laboratory-in-a-van] is a brilliant way to reduce the barriers to testing, instead taking the lab to communities who may be less likely—or unable—to access the necessary clinic or labs,” microbiologist Anne Wyllie, PhD, a research scientist who helped develop the PCR test deployed by the mobile lab told Yale Daily News. Wyllie works in the Department of Epidemiology of Microbial Diseases at Yale School of Public Health. “We are actively working with our community partners to identify how we can best serve their communities,” she added. (Photo copyright: Yale School of Medicine.)
Mobile Lab’s Capabilities
Collecting samples, processing, and delivering same-day COVID-19 results was the initial goal but that plan has expanded, Yale School of Medicine noted in a news release.
“Same-day onsite delivery of test results is an added benefit for communities and individuals without access to Wi-Fi or the ability to receive private health information electronically,” Yale added.
The mobile van is staffed with trained clinical laboratory technicians as well as community health navigators who provide both healthcare information and proper follow-up connections as needed for patients who receive positive COVID-19 results. The van runs off power from outdoor electrical outlets at each location and currently serves historically underserved populations in Hartford, Middlesex, Fairfield, New Haven, and New London counties, Yale noted.
“The van allows us to bring our services, as well as healthcare information, directly to communities where they are needed,” said Angelique Levi, MD, Associate Professor, Vice Chair and Director of Pathology Reference Services, and CLIA Laboratory Medical Director in the Department of Pathology at Yale University School of Medicine in a news release.
Launch of a High Complexity Molecular Lab on Wheels
YPL and YSPH collaborated to make the mobile lab a reality. YSPH created the saliva-based COVID-19 test and YPL “provided clinical validation necessary to get the testing method ready for emergency use authorization by the US Food and Drug Administration,” Yale noted.
“YPL recognized the need to be closer to the front lines of patient care and that retrofitting a fully licensed, high complexity molecular laboratory into a consumer-sized van was the right next step,” Chen Liu, MD, PhD, Chair of the Department of Pathology at Yale School of Medicine, noted in a Yale news release. This “gives us options to efficiently deliver accurate diagnostic information when and where it’s needed,” he added.
Throughout the COVID-19 pandemic, the Connecticut Department of Public Health, the City of New Haven, and various community organizations partnered with YPL, YSPH, and the SalivaDirect team to offer free SARS-CoV-2 testing to the public at two different sites in New Haven.
Principal investigators Levi and microbiologist Anne Wyllie, PhD, who helped develop the PCR test deployed by the mobile, lab led the Yale lab-in-a-van research project.
Flambeau Diagnostics, a biomedical company that specializing in mobile lab testing, worked with the Yale team to design and implement the mobile lab van.
“According to Wyllie, the new YSPH and YPL initiative utilizes one of the former Flambeau vans that had been retrofitted for clinical testing,” a Yale news release noted.
Kat Fajardo, Laboratory Manager at Yale University, added custom pieces of equipment to ensure seamless PCR testing. One was a Magnetic Induction Cycler (Mic) measuring only six by six inches. The Mic allowed for measurement of 46 biological specimens, while it’s diminutive size freed up space on the van’s countertop. This allowed lab techs to process specimens concurrently while also providing COVID-19 testing, according to a Yale news release.
Additionally, the van has a Myra portable robotic liquid handler which is “designed to automate the process of moving clinical specimens between vials,” the news release notes.
“What we wanted to do is run high complexity testing in the van, with a reduced timeframe, and then be able to get the results out to the patients as soon as we possibly could,” Fajardo stated.
Exploring the Mobile Laboratory’s Potential
According to a news release, YPL and YSPH consult with community partners to select locations for the mobile lab to visit. These partners include:
APT Foundation (New Haven County, in addition to others.
Although the van was initially used to provide SalivaDirect COVID-19 testing to vulnerable populations, YPL is working with its partners in those communities to identify other testing needs beyond COVID.
The Yale team is considering additional offerings and support such as the addition of a social worker as well as expanding lung health awareness beyond COVID-19 to other respiratory diseases. Also under consideration:
Vaccinations including for COVID-19 and Hepatitis B, and
Health education and materials for harm reduction and STI prevention, a Yale news release noted.
Yale’s Laboratory-in-a-Van program is a consumer-facing effort that is bringing much needed clinical lab services to traditionally underserved communities in Connecticut. Clinical laboratories throughout the nation could do the same with remote or homebound patients who cannot reach critical care.
New guidelines also advise people to limit their vitamin D supplementation to recommended daily doses
Clinical laboratories may eventually receive fewer doctors’ orders for vitamin D testing thanks to new guidelines released by the Endocrine Society. The new Clinical Practice Guideline advises against “unnecessary testing for vitamin D levels.” It also urges healthy people, and those 75-years of age or younger, to avoid taking the vitamin at levels above the daily recommended amounts, according to a news release.
Even though the Endocrine Society does recommend vitamin D supplements for certain groups, it advises individuals to hold off on routine testing. That’s because there appears to be uncertainty among ordering clinicians about what to do for patients based on their vitamin D test results.
“When clinicians measure vitamin D, they’re forced to decide what to do about it. That’s where questions about the levels come in. And that’s a big problem. So, what this panel is saying is ‘Don’t screen,’” Clifford Rosen, MD, Director of Clinical and Translational Research and Senior Scientist, Maine Medical Center Research Institute at the University of Maine, told Medscape Medical News.
“We have no data that there’s anything about screening that allows us to improve quality of life. Screening is probably not worthwhile in any age group,” he added.
“This guideline refers to people who are otherwise healthy, and there’s no clear indication for vitamin D, such as people with already established osteoporosis. This guideline is not relevant to them,” the author of the Endocrine Society guideline, Anastassios G. Pittas, MD (above), Professor of Medicine at Tufts University School of Medicine in Boston, told Medscape Medical News. This new guideline could result in doctors ordering fewer vitamin D tests from clinical laboratories. (Photo copyright: Tufts University.)
Vitamin D Screening Not Recommended for Certain Groups
The Endocrine Society’s new clinical guidelines advise healthy adults under 75 years of age to refrain from taking vitamin D supplements that exceed US Institute of Medicine—now the National Academy of Medicine (NAM)—recommendations.
Additionally, these updated guidelines:
Recommend vitamin D supplements at levels above NAM recommendations to help lower risks faced by children 18 years and younger, adults 75 and older, pregnant women, and people with prediabetes.
Suggest daily, lower-dose vitamin D (instead of non-daily, higher-dose of the vitamin) for people 50 years and older who have “indications for vitamin D supplementation or treatment.”
Advise “against routine testing for 25-hydroxyvitamin D [aka, calcifediol] levels” in all the above groups “since outcome-specific benefits based on these levels have not been identified. This includes 25-hyrdoxyvitamin D screening in people with dark complexion or obesity.”
One exception to the guideline applies to people with already established osteoporosis, according to the guideline’s author endocrinologist Anastassios G. Pittas, MD, Chief of Endocrinology, Diabetes and Metabolism; Co-Director, Tuft’s Diabetes and Lipid Center; and Professor of Medicine at Tufts University School of Medicine in Boston.
Vitamin D’s Link to Disease Studied
During a panel discussion at the Endocrine Society’s annual meeting, members acknowledged that many studies have shown relationships between serum concentrations of 25-hydroxy vitamin D (25(OH)D) and physical disorders including those of musculoskeletal, metabolic, and cardiovascular systems. Still, they questioned the link of vitamin D supplementation and testing with disease prevention.
“There is paucity of data regarding definition of optimal levels and optimal intake of vitamin D for preventing specific diseases. … What we really need are large-scale clinical trials and biomarkers so we can predict disease outcome before it happens,” said Panel Chair Marie Demay, MD, Endocrinologist, Massachusetts General Hospital, and Professor of Medicine, Harvard Medical School, Boston, Medscape Medical News reported.
Meanwhile, in their Journal of Clinical Endocrinology and Metabolism paper, the researchers note that use of supplements (1,000 IU or more per day) increased from 0.3% to 18.2%, according to the National Health and Nutrition Examination Survey (NHANES) conducted by the National Center for Health Statistics (NCHS), CDC, for the years 1999-2000 and 2013-2014.
“The use of 25(OH)D testing in clinical practice has also been increasing; however, the cost effectiveness of widespread testing has been questioned, especially given the uncertainty surrounding the optimal level of 25(OH)D required to prevent disease,” the authors wrote.
“Thus, the panel suggests against routine 25(OH)D testing in all populations considered,” the researchers stated at the Endocrine Society annual meeting.
Other Groups Weigh-in on Vitamin D Testing
Pathologists and medical laboratory leaders may recall the explosion in vitamin D testing starting about 20 years ago. Vitamin D testing reimbursed by Medicare Part B “increased 83-fold” during the years 2000 to 2010, according to data cited in an analysis by the American Academy of Family Physicians (AAFP).
Also, the US Preventive Services Task Force (USPSTF) said in a statement that there is not enough information to “recommend for or against” testing for vitamin D deficiency.
“No organization recommends population-based screening for vitamin D deficiency, and the American Society for Clinical Pathology recommends against it,” the USPSTF noted.
Clinical Laboratories Can Get the Word Out
The vitamin D debate has been going on for a while. And the latest guidance from the Endocrine Society may cause physicians and patients to stop ordering vitamin D tests as part of annual physicals or in routine screenings.
Medical laboratories can provide value by ensuring physicians and patients have the latest information about vitamin D test orders, reports, and interpretation.
Infection control teams and clinical laboratory managers may want to look at this new product designed to improve the diagnosis and treatment of sepsis
Accurate and fast diagnosis of sepsis for patients arriving in emergency departments is the goal of a new product that was just cleared by the federal Food and Drug Administration (FDA). It is also the newest example of how artificial intelligence (AI) continues to find its way into pathology and clinical laboratory medicine.
Sepsis is one of the deadliest killers in US hospitals. That is why there is interest in the recent action by the FDA to grant marketing authorization for an AI-powered sepsis detection software through the agency’s De Novo Classification Request. The DNCR “provides a marketing pathway to classify novel medical devices for which general controls alone, or general and special controls, provide reasonable assurance of safety and effectiveness for the intended use, but for which there is no legally marketed predicate device,” the FDA’s website states.
Unlike a single analyte assay that is run in a clinical laboratory, Prenosis’ AI/ML software uses 22 diagnostic and predictive parameters, along with ML algorithms, to analyze data and produce a clinically actionable answer on sepsis.
It is important for clinical laboratory managers and pathologists to recognize that this diagnostic approach to sepsis brings together a number of data points commonly found in a patient’s electronic health record (EHR), some of which the lab generated and others the lab did not generate.
“Sepsis is a serious and sometimes deadly complication. Technologies developed to help prevent this condition have the potential to provide a significant benefit to patients,” said Jeff Shuren, MD, JD, Director of the FDA’s Center for Devices and Radiological Health, in a statement. “The FDA’s authorization of the Prenosis Sepsis ImmunoScore software establishes specific premarket and post-market requirements for this device type.” Clinical laboratory EHRs contain some of the data points Prenosis’ diagnostic software uses. (Photo copyright: US Food and Drug Administration.)
How it Works
To assist doctors diagnose sepsis, the ImmunoScore software is first integrated into the patient’s hospital EHR. From there, it leverages 22 parameters including:
White blood cell count to produce a score that informs caregivers of the patient’s risk for sepsis within 24 hours, MedTech Dive reported.
Instead of requiring a doctor or nurse to look at each parameter separately, the SaMD tool uses AI “to evaluate all those markers at once”, CNBC noted. It then produces a risk score and four discrete risk stratification categories (low, medium, high, and very high) which correlate to “a patient’s risk of deterioration” represented by:
By sharing these details—a number from one to 100 for each of the 22 diagnostic and predictive parameters—Sepsis ImmunoScore helps doctors determine which will likely contribute most to the patient’s risk for developing sepsis, MedTech Dive reported.
“A lot of clinicians don’t trust AI products for multiple reasons. We are trying very hard to counter that skepticism by making a tool that was validated by the FDA first, and then the second piece is we’re not trying to replace the clinician,” Bobby Reddy Jr., PhD, Prenosis co-founder and CEO, told MedTech Dive.
Big Biobank and Blood Sample Data
Prenosis, which says its goal is the “enabling [of] precision medicine in acute care” developed Sepsis ImmunoScore using the company’s own biobank and a dataset of more than 100,000 blood samples from more than 25,000 patients.
AI algorithms drew on this biological/clinical dataset—the largest in the world for acute care patients suspected of having serious infections, according to Prenosis—to “elucidate patterns in rapid immune response.”
“It does not work without data, and the data started at Carle,” said critical care specialist Karen White, MD, PhD, Carle Foundation Hospital, St. Louis, MO, in the news release. “The project involved a large number of physicians, research staff, and internal medicine residents at Carle who helped recruit patients, collect data, and samples,” she said.
Opportunity for Clinical Laboratories
Sepsis is a life-threatening condition based on an “extreme response to an infection” that affects nearly 1.7 million adults in the US each year and is responsible for 350,000 deaths, according to US Centers for Disease Control and Prevention (CDC) data.
A non-invasive diagnostic tool like Sepsis ImmunoScore will be a boon to emergency physicians and the patients they treat. Now that the FDA has authorized the SaMD diagnostic tool to go to market, it may not be long before physicians can use the information it produces to save lives.
Clinical laboratory managers inspired by the development of Sepsis ImmunoScore may want to look for similar ways they can take certain lab test results and combine them with other data in an EHR to create intelligence that physicians can use to better treat their patients. The way forward in laboratory medicine will be combining lab test results with other relevant sets of data to create clinically actionable intelligence for physicians, patients, and payers.
