Researchers at the University of Texas at Arlington, in collaboration with Shani Biotechnologies, a local company, have created a point-of-care device that can accurately measure hemoglobin levels and perform pulse oximetry in individuals with dark skin. Currently, methods of determining hemoglobin levels at the point of care, such as pulse oximetry, are inaccurate in individuals with higher levels of melanin in the 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 blue-green light in addition to assessing skin color and using algorithms to calculate 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 illnesses, such as COVID-19, measurements can indicate whether a dangerous worsening is occurring and can be a determinant of whether a patient needs urgent treatment.
Unlike traditional methods for determining hemoglobin levels in blood, which require expensive equipment and blood sampling, a major advantage of pulse oximeters is their affordability and portability, enabling point-of-care measurements. The device shines light through the skin, usually a finger or earlobe, and then calculates how much light was absorbed to infer the blood’s oxygen concentration.
Despite its usefulness, this technique 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 between 520–580 nm, which places the light in the green/blue region of the spectrum. This is in contrast to the red-infrared light used in conventional pulse oximeters. The system also assesses skin tone using the Von Luschan Chromatic Scale and then uses an algorithm to account for the amount 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 wavelengths, light scattering and the effect of melanin in the skin. The scientific community should open their minds to the idea of a green light for these measurements. The Shani device has great potential to eliminate this racial inequality.
Study in BMJ innovations: Innovative technology to eliminate racial bias in non-invasive point-of-care (POC) hemoglobin and pulse oximetry
About: The University of Texas at Arlington