Multiple studies have shown that people with darker skin pigmentation run a higher risk of being misdiagnosed and undertreated than patients with lighter skin due to inaccurate oxygen level readings
Now, scientists at multiple institutions are working to improve the basic pulse oximeter’s design by making it capable of measuring multiple biomarkers, as well as addressing long-standing inaccuracies in the device when used on people with darker skin pigmentation.
This ongoing research demonstrates how new technologies are enabling innovators to add useful functions to standard, well-accepted devices.
Valencia Koomson, PhD (above), Associate Professor, Electrical and Computer Engineering, and head of the Advanced Integrated Circuits and Systems Lab at Tufts University, has developed a pulse oximeter that measures oxygenation in tissue, rather than in blood. Her approach could ensure patients with darker skin pigmentation will be accurately diagnosed at the point-of-care. Though generally not used in clinical laboratory settings, medical technologists will be interested to learn of these new innovations in pulse oximeters. (Photo copyright: Tufts University.)
Measuring Tissues Instead of Blood
The pulse oximeter—a device that attaches to a person’s finger—uses red and infrared light to measure blood oxygen saturation (SpO2) and display pulse rate.
Studies in 2022 that looked into how hospitals administered oxygen to different patients found that inconsistent pulse oximeter readings could cause caregivers to administer less oxygen than is actually needed to people with darker skin pigmentation.
This is because melanin in the skin can interfere with “absorption of light used to measure oxygenated blood in a person’s finger,” according to a National Science Foundation (NSF) news story. Such inaccurate pulse oximeter readings can lead to “inaccurate readings and poorer treatment outcomes” for people with dark skin tones, the NSF wrote.
“Addressing this problem will require innovation in pulse oximeter design and revised regulatory standards,” said Valencia Koomson, PhD, Associate Professor, Electrical and Computer Engineering, Tufts University, Medford, Massachusetts, in the NSF news story.
Koomson, who leads the Advance Integrated Circuit and Systems Lab at Tufts, has developed a prototype pulse oximeter device, which NSF explained, measures oxygenation in biological tissues instead of blood.
“My lab’s work on pulse oximeter devices will provide an alternative technology to address many confounding factors that affect pulse oximeter accuracy, including skin pigmentation, motion artifact, and others,” Koomson said.
National Public Radio (NPR) said Koomson’s device has built-in “technology that can measure a person’s skin tone.”
“We can send more light if there’s a higher level of melanin present, so that melanin doesn’t become a confounding factor that obscures our results,” Koomson told NPR.
Another Pulse Oximeter Redesign
Another new approach to pulse oximetry was developed at Brown University in Providence, Rhode Island.
Rutendo Jakachira, Research Assistant, School of Engineering, and a PhD student in physics, turned to new optical techniques to address the challenge of oxygen saturation levels in dark skin tones, according to a Brown University news release.
Jakachira and Kimani Toussaint, PhD, Professor of Engineering and Senior Associate Dean in the School of Engineering, say they have created possibly the first LED-based light source to emit radially polarized light.
When the LED passes light through a person’s finger, the device calculates the amount of light the hemoglobin in the blood absorbed, NPR explained.
“We did a preliminary study on about five people, and although it was a small study, the results are promising,” said Jakachira, who plans a larger study and clinical trial.
Study Suggests Patients with Darker Skin May Have Received Delayed COVID-19 Care
The researchers analyzed electronic health record (EHR) data from 43,753 patients at Sutter Health in Sacramento, California, who had SpO2 measurements done between January 2020 and February 2022, and 8,735 patients seen for COVID-19 between July 2020 and February 2021 in the hospital’s emergency department.
In their AJE paper, they wrote, “We investigated whether or not pulse oximetry systematically underestimated oxygen saturation in patients who identified as NHB [non-Hispanic Black/African-American] as compared with NHW [non-Hispanic White] counterparts. We also assessed whether or not differences in oxygen saturation measurement affected hospital admission, care delivered, or return to the hospital post discharge among patients with COVID-19.
“We found evidence of differential pulse oximeter measurement error in NHB individuals, resulting in nonrandom overestimation of blood oxygenation as compared with NHW individuals. NHB individuals were also more likely to have hypoxemia [abnormally low oxygen levels in the blood] not detected by pulse oximetry.
“For NHB patients presenting in the ED with COVID-19, we found that overestimation of oxygen saturation was associated with underestimation of the need for admission and underestimation of the need for treatment with dexamethasone and supplemental oxygen. Additionally, we observed associated delays in dexamethasone initiation and initiation of oxygen supplementation.
“There are also broader implications beyond COVID-19, as differential pulse oximeter accuracy has the potential to exacerbate disparities for any condition that relies upon blood oxygenation measurement to inform clinical decision-making.”
Importance of Accurate Readings
Developing pulse oximeters that are accurate for all people, regardless of skin tone, is clearly an important breakthrough. Medical laboratory leaders and pathologists recognize that SpO2 data—along with clinical laboratory test results—are critical for successful diagnostics and treatment. Thus, new technologies that add useful functions to well-accepted devices are positive developments and worth watching.
As cognitive and cloud computing continue to advance, and mobile technologies become more accessible across the globe, innovative apps and mobile attachments are using algorithms to replace the need for complex and time-consuming diagnostic tests
Mobile healthcare—also known as mHealth—is attracting plenty of research dollars as entrepreneurs look for ways improve consumers’ access to various medical services in ways that could reduce healthcare costs. For that reason, some mHealth solutions may be used by clinical laboratories and pathology groups to give patients faster access to diagnostic services and information about medical laboratory tests.
Most mHealth solutions excel at doing a single, defined task well. In some cases, they are faster and as accurate as human-based testing or observation. However, few solutions can tackle complex diagnostics, such as determining the pathogens involved in sepsis. And mHealth cannot replace the human element of communication and empathy, which will always have a place in the medical process. (more…)
Researchers determined that as many as nine successive capillary blood drops must be collected and tested to achieve results that would be comparable to testing with venous blood
A new study is raising questions about the implications of using fingerprick blood samples for point-of-care tests. Done by researchers at Rice University’s Department of Bioengineering, the study suggests clinicians use measurements with caution when assessing patients’ conditions based on the results of clinical laboratory tests using a single drop of capillary blood collected by fingerstick.
Pathologists and clinical laboratory scientists were quick to call attention to the study, based on the press release Rice University issued. That’s because, for almost 30 years, medical laboratories have struggled to correlate the results for such biomarkers as glucose. It is common for capillary blood specimen collected by finger stick and tested on a point-of-care device to produce different results for the same patient when compared with that of a venous specimen tested on the automated, high-volume analyzes in a central laboratory. The Rice researchers offer useful insights about such variation. (more…)
New lab test market could open up if research findings lead Consumer Reports and nine medical specialty associates join forces to target the overuse of certain diagnostic procedures, including some medical laboratory tests
For years, pathologists and physicians have spoken out about the overuse of medical laboratory tests and other diagnostic procedures. Now an interesting alliance of a medical specialty association and Consumer Reports has come together with a highly-publicized plan designed to reduce unnecessary or inappropriate testing by encouraging physicians to more deeply involve patients in the process.
It is the American Board of Internal Medicine Foundation (ABIMF) that is working with Consumer Reports. Their common goal is to stanch the overuse of unnecessary healthcare tests and procedures that do not improve patient outcomes and do run up healthcare costs. Experts estimate the wasteful use of healthcare resources accounts for as much as 30% of current healthcare costs in the United States.
The program is called “Choosing Wisely” (CW). According to a story in Modern Healthcare (MH), “Choosing Wisely” is a campaign to get physicians and patients to discuss whether a particular test is likely to improve patient health or outcome.
Pictured above is the press conference conducted by the American Board of Internal Medicine Foundation (ABIMF) to announce the launch of the “Choosing Wisely” campaign. The goal of this campaign is to reduce overutilization or unnecessary ordering of diagnostic procedures. Each of nine medical specialty associations has put forth a list of specific diagnostic procedures that should be part of this campaign and a number of clinical laboratory tests are on these lists. (Photo copyright by American Society of Nephrology.)
Participating in this initiative are about 375,000 physicians in nine specialty societies. Each of these nine medical specialty groups has identified five diagnostic tests or procedures within their specialty area that warrant re-evaluation by physicians and patients as to whether they will provide useful information or lead to a positive outcome. Clinical laboratory managers and pathologists will be interested to learn that a number of these medical specialty associations have included clinical laboratory tests on their respective lists.
“What we’re asking for is for people to have a conversation,” stated Daniel B. Wolfson, M.H.S.A., ABIM Foundation Executive Vice President and Chief Operating Officer, in the MH story. “These are not rules; they are guidelines used to guide most—but not all—cases,” he explained.
“These societies have shown tremendous leadership in starting a long overdue and important conversation between physicians and patients about what care is really needed,” said Christine K. Cassel, M.D., President and Chief Executive Officer of the ABMF. “Physicians, working together with patients, can help ensure the right care is delivered at the right time for the right patient.” She was quoted in a Choosing Wisely press release.
According to the release, Consumer Reports is working with American Association of Retired People (AARP) and other organizations representing the lay public to get the word out about the “Choosing Wisely” campaign.
Specialist Physicians Identify Some Medical Laboratory Tests for Review
Below are listed the recommendations made by the different medical specialty associations that identify a clinical laboratory test:
Don’t perform unproven diagnostic tests, such as immunoglobulin G (IgG) testing or an indiscriminate battery of immunoglobulin E (IgE) tests, in the evaluation of allergy.
Don’t routinely do diagnostic testing in patients with chronic urticaria.
Don’t recommend replacement immunoglobulin therapy for recurrent infections unless impaired antibody responses to vaccines are demonstrated.
In patients with low pretest probability of venous thromboembolism (VTE), obtain a high-sensitive D-dimer measurement as the initial diagnostic test; don’t obtain imaging studies as the initial diagnostic test.
Don’t perform routine cancer screening for dialysis patients with limited life expectancies without signs or symptoms.
Don’t administer erythropoiesis-stimulating agents (ESAs) to chronic kidney disease (CKD) patients with hemoglobin levels greater than or equal to 10g/dL without symptoms or anemia.
In its coverage of the “Choosing Wisely” initiative, Clinical Laboratory News, a publication of the American Association for Clinical Chemistry, (AACC) reported that the utilization changes CW seeks may sound like bad news for the lab,. But sometimes these types of program can end up promoting appropriate clinical laboratory testing over other options, the writer noted.
The “Choosing Wisely” initiative, at a minimum, does provide another opportunity for pathologists and clinical laboratory managers to add value to physicians and their patients by helping clinicians have confidence they they are ordering the right test at the right time, supported by evidence-based medicine (EBM) guidelines.
HemoCue has global revenues of about $90 million per year, according to Quest Diagnostics. Its products are sold internationally. It provides point-of-care blood tests for hemoglobin, along with products for professional glucose and microalbumin testing. HemoCue’s handheld systems are used to screen for anemia and other conditions in physicians’ offices, blood banks, hospitals, diabetes clinics, and public health clinics. The company is currently developing hand-held systems to measure white blood cell count. Quest Diagnostics purchased HemoCue from a European-based private equity firm, EQT II BV.
Quest Diagnostics intends to integrate HemoCue’s handheld systems with its Care360 Portal, which gives doctors access to lab and medication records, patient medical history, and remote ordering of lab testing or prescriptions. Quest Diagnostics also said the deal will allow it to expand into international markets. “Technology is enabling diagnostic testing to move closer to the patient, and the acquisition of HemoCue and its exciting product pipeline gives us a strong presence in this emerging market,” said Surya N. Mohapatra, Chairman and CEO of Quest Diagnostics.
Dark Daily notes that Quest Diagnostics has been under stress to defend the business it gets from doctors who serve United HealthCare patients. The timing and nature of this acquisition have the appearance of a strategic move to shift the attention of investors away from Quest’s challenges with its United HealthCare book of business. As well, HemoCue’s $90 million in annual revenues will also help to replace revenue that Quest Diagnostics is expected to lose as a result of being excluded as a UnitedHealth provider in most markets since January 1, 2007.
