News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

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News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

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Innovators Develop Multi-Analyte Pulse Oximeters That Accurately Read Oxygen Levels in People with Darker Skin Pigmentation

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

Though pulse oximeters are not a standard clinical laboratory device, clinical laboratory scientists (aka, medical technologists) know of them and understand their function, particularly with hospital patients.

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

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.

NSF supports her pulse oximeter research through the National Science Foundation Partnerships for Innovation (PFI) program.

“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

Meanwhile, a study published in the American Journal of Epidemiology (AJE) suggested pulse oximeter errors may have led to a 4.5-hour delay in COVID-19 treatment of patients with darker skin pigmentation, according to a news release from the University of California San Francisco.

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.    

Donna Marie Pocius

Related Information:

Researcher Addresses Longstanding Problem with Pulse Oximeters and Dark-skinned Patients

When it Comes to Darker Skin, Pulse Oximeters Fall Short

Brown PhD Student Working to Correct Skin Color Bias in Pulse Oximeters

Pulse Oximeters Don’t Work as Well on Darker Skin, Leading to Flawed COVID-19 Care

Racial Disparities in Pulse Oximeter Device Inaccuracy and Estimated Clinical Impact on COVID-19 Treatment Course

International Team of Scientists Develop Smart Diaper That Alerts Parents When It Is Soiled and Needs to Be Changed

Not the first smart diaper to come along, but consumers seem unready for diapers that can flag urinary tract infections and other biomarkers usually tested by clinical laboratories

Will wonders never cease? For centuries, parents had only their own senses to determine when infants needed diaper changing. Today, however, caregivers can rely on “smart diapers” to send alerts when a diaper is soiled. Crying, smelly babies may no longer be the gold standard in diaper management. But are smart diapers practical?

Scientists at Penn State University in collaboration with scientists from the Hebei University of Technology and Tianjin Tianzhong Yimai Technology Development Company in China think so.

Funded by the National Institutes of Health (NIH) and the National Science Foundation (NSF), Penn State’s new smart diaper is based on a simple pencil-on-paper design that utilizes an electrode sensor array treated with a sodium chloride solution that detects dampness when urine is present.

The sensor array is “so cheap and simple” it “could clear the way for wearable, self-powered health monitors for use not only in ‘smart diapers’ but also to predict major health concerns like cardiac arrest and pneumonia,” a Penn State new release noted.

However, clinical laboratory managers following similar developments probably know that this is not the first scientific effort to develop a smart diaper that uses some type of sensor to detect a biomarker and issue an alert to the wearer or caregivers.

For example, nine years ago, In “New ‘Smart Diaper’ Tests Baby’s Urine for Urinary Tract Infections, Dehydration, and Kidney Problems—then Alerts Baby’s Doctor,” Dark Daily reported on a digital smart diaper invented by New York startup Pixie Scientific that constantly monitors a baby’s health to detect urinary tract infections, kidney problems, or dehydration before the health issue escalates. That smart diaper also uses a smartphone app to send data to the baby’s doctor.

In this latest research effort, the scientists published their findings in the journal Nano Letters, titled, “Pencil-on-Paper Humidity Sensor Treated with NaCl Solution for Health Monitoring and Skin Characterization.”

Huanyu "Larry" Cheng, PhD

“Our team has been focused on developing devices that can capture vital information for human health,” said Huanyu “Larry” Cheng, PhD (above), the James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics at Penn State in a news release. “The goal is early prediction for disease conditions and health situations, to spot problems before it is too late.” This is yet another example of how researchers are working to take more testing out of clinical laboratories and offer unique assays that can be used as wearables—whether as a diaper, a skin patch, or a smart watch. (Photo copyright: Penn State University.)

This Smart Diaper Is as Simple to Use as Paper and Pencil

The Penn State sensor array takes advantage of how paper naturally reacts to wetness and utilizes the graphite in pencil marking to interact with the water molecules and sodium chloride.

Once the water molecules are absorbed by the paper, the sodium chloride solution becomes ionized and electrons start to stream towards the graphite. This movement sets off the sensor, which is extremely sensitive to humidity. According to the study, the sensor can provide accurate readings over a wide range of humidity levels, from 5.6% to 90%.

“We wanted to develop something low-cost that people would understand how to make and use, and you can’t get more accessible than pencil and paper,” said Li Yang, PhD, a professor in the School of Artificial Intelligence at China’s Hebei University of Technology and one of the authors of the study, in the Penn State news release.

“You don’t need to have some piece of multi-million-dollar equipment for fabrication. You just need to be able to draw within the lines of a pre-drawn electrode on a treated piece of paper. It can be done simply and quickly.”

The diaper is connected to a tiny lithium battery. When the sensor recognizes an increase in humidity the battery powers transmission of the change to a smartphone via Bluetooth technology. This notification informs caregivers that it is time to change the diaper.

“That application was actually born out of personal experience,” explained Huanyu “Larry” Cheng, PhD, James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics at Penn State, one of the authors of the study and father to two young children. “There’s no easy way to know how wet is wet, and that information could be really valuable for parents. The sensor can provide data in the short-term, to alert for diaper changes, but also in the long-term, to show patterns that can inform parents about the overall health of their child.”

Do Consumers Want Smart Diapers?

Research into such wearable sensors has been gaining momentum in the scientific community as a novel way to detect and deal with several medical conditions. The Penn State team hopes that devices such as their smart diaper can be used in the future to alert caregivers about the overall health of their children and clients.

“Our team has been focused on developing devices that can capture vital information for human health,” Cheng said. “The goal is early prediction for disease conditions and health situations, to spot problems before it is too late.” 

Previous research teams have had similar smart diaper goals.

In “Researchers in Japan Have Developed a ‘Smart’ Diaper Equipped with a Self-powered Biosensor That Can Monitor Blood Glucose Levels in Adults,” we covered how a team of researchers at Tokyo University of Science (TUS) in Japan had developed a diaper that detects blood glucose levels in individuals living with diabetes, a debilitating illness.

However, these types of products have yet to gain significant popularity with consumers. Regardless, sales projections for smart diapers remain positive.

According to a MarketsandMarkets report, the smart diaper market, estimated to be $646 million (US) in 2021, is expected to surpass $1.5 billion by 2026. The demand for smart diapers, the report notes, is increasing due to:

  • Growing elderly populations,
  • Rising disposable incomes,
  • Increasing personal hygiene awareness,
  • Growing populations in emerging countries, and
  • Expanding preference for advanced technology when it comes to health.

So, it’s uncertain if consumers are now ready for a device in their baby’s diaper telling them it’s time for a change. Regardless, researchers will likely continue developing tools that combine new diagnostics with existing products to help people better understand and monitor their health and the health of their loved ones.

Meanwhile, clinical laboratory managers and pathologists can remain on the alert for future published studies and press releases announcing new wearable items containing sensors, such as smart diapers. The unanswered question is whether both consumers and healthcare professionals will consider these novel inventions useful devices in the care of young and old alike.

—JP Schlingman

Related Information:

Researchers Developed a “Smart Diaper” That Sends Notifications to Parents’ Phones

New Sensor Enables ‘Smart Diapers,’ Range of Other Health Monitors

Pencil-on-Paper Humidity Sensor Treated with NaCl Solution for Health Monitoring and Skin Characterization

Diaper Which Signals Time for Change by Chinese Team

New ‘Smart Diaper’ Tests Baby’s Urine for Urinary Tract Infections, Dehydration, and Kidney Problems—then Alerts Baby’s Doctor

Researchers in Japan Have Developed a ‘Smart’ Diaper Equipped with a Self-powered Biosensor That Can Monitor Blood Glucose Levels in Adults

Smart Diapers Market by End-Use (Babies, Adults), Technology (RFID Tags, Bluetooth Sensors), and Geography (North America, Asia Pacific, Europe, and Rest of World) (2022—2026)

The Smart Diaper is Coming. Who Actually Wants It?

New Approach to Detecting Circulating Tumor Cells in Blood Uses Acoustic Sound Waves and Researchers Are Hopeful that the Technology Can Lead to a Medical Laboratory Test

Innovative device uses acoustic sound waves to gently separate circulating cancer cells from white blood cells

In many respects, the ability to separate and identify circulating tumor cells (CTCs) is one of the holy grails of cancer diagnostics. It is widely believed that a clinical laboratory test that can effectively identify CTCs would contribute to earlier detection of cancer and improved outcomes for caner patients.

Pathologists will be interested to learn about a useful new tool that can flag circulating tumor cells. Researchers say that this approach enables them to determine if a cancerous tumor is going to spread, without tagging tumor cells with harsh chemicals. This gentler alternative to current diagnostic methods involves an innovative device that uses “tilted” sound waves to sort tumor cells from white blood cells, noted a report in Headlines & Global News.

This device is about the size of a cell phone. It was developed by a team of scientists from the Pennsylvania State University (PSU), Massachusetts Institute of Technology (MIT) and Carnegie Mellon University (CMU).

Their research was funded by the National Institutes of Health (NIH) and the National Science Foundation (NSF). The research study was published by PNAS, the journal of the U.S. National Academy of Sciences, January 5, 2015. (more…)