Researchers at the University of Texas at Arlington, in collaboration with Shani Biotechnologies, a local firm, have created a point-of-care device that can accurately measure hemoglobin levels and perform pulse oximetry in individuals with dark skin. At present, methods to determine hemoglobin levels at the point of care, such as pulse oximetry, are inaccurate in individuals with higher levels of melanin in their skin, and there is a clear need to develop alternatives that work for everyone. Instead of the red-infrared light used by common pulse oximeters, this new device relies on a blue-green light in addition to assessing skin tone and using algorithms when calculating hemoglobin levels and oxygen saturation.
Pulse-oximeters are a very useful way to determine how much oxygen the hemoglobin in your blood is carrying. For those with potentially serious respiratory diseases, such as COVID-19, the readings can indicate if a dangerous exacerbation is occurring and can be the decider as to whether a patient requires urgent treatment.
Unlike conventional approaches to determining blood hemoglobin levels, which require expensive equipment and blood draws, a major advantage of pulse oximeters is their affordability and portability, allowing point-of-care measurements. The device shines light through the skin, typically a finger or ear-lobe, and then calculates how much light was absorbed to infer the degree of blood oxygenation.
Despite its utility, this technology does not work perfectly for everyone. In fact, pulse oximeters can be unacceptably inaccurate in those with dark skin, highlighting the need for more universal solutions. In an effort to develop a better alternative, these researchers have created a new type of device that can measure and account for skin tone.
The new technology uses light emitting diodes (LEDs) with wavelengths ranging from 520–580 nm, placing the light in the green/blue area of the spectrum. This contrasts with the red-infrared light used in conventional pulse oximeters. The system also assess skin tone using the Von Luschan Chromatic Scale, and then employs algorithms to account for the level of melanin detected.
“We have used the green-blue light and have successfully tested the device in preclinical and clinical studies,” said Vinoop Daggubati, a researcher involved in the study. “Our group has addressed the issues around shorter wavelength, scattering of light and the impact of skin melanin. The scientific community should open its mind to the concept of green light for these measurements. The Shani device has huge potential to eliminate this racial disparity.”
Study in BMJ Innovations: Innovative technology to eliminate the racial bias in non-invasive, point-of-care (POC) haemoglobin and pulse oximetry measurements