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Often when Dr. Thomas Valley sees a new patient in the intensive care unit at Michigan Medicine in Ann Arbor, he clamps a pulse oximeter on their finger – one of the many devices he uses to gauge their health and what course of care they might require, whether they are a child having seizures, a teenage car accident victim or an older person with Covid-19.

But recently, Valley, an assistant professor in the University of Michigan’s Division of Pulmonary and Critical Care, realized first-hand that the small device may yield less accurate oxygen readings in patients with dark skin.

One end of the device sends light through the finger while a sensor on the other side receives this light and uses it to detect the color of your blood; bright red blood is highly oxygenated, while blue or purplish blood is less. If the device isn’t calibrated for darker skin tones, the pigmentation of the skin could affect how the light is absorbed by the sensor, leading to flawed oxygen readings.

New immune-evading Omicron subvariant BA.5 is now dominant in the U.S.—and previous heavy hitter “stealth Omicron” is now a shadow of its former self, according to federal health data released Tuesday.

BA.5 is estimated to have caused nearly 54% of COVID infections in the U.S. last week, according to data from the U.S. Centers for Disease Control and Prevention. Along with twin variant BA.4, it swept South Africa this spring thanks to its ability to evade immunity from both prior infection and vaccination.

The week before that, the two variants combined made up slightly more than half of U.S. cases. But last week, BA.5 accomplished the same feat alone, without the help of BA.4, which came in third at 16.5%.

Near-invisible graphene tattoos deliver high-speed and long-term continuous monitoring of blood pressure with high accuracy.

Wrapping a cuff around a patient’s arm and inflating it to measure blood pressure is one of the most routinely performed medical tests. It provides a quick and reliable assessment of cardiovascular health, as blood pressure is an independent predictor of all-cause mortality. But such arm cuffs are bulky and uncomfortable, making them impractical for continuous monitoring outside of clinics.

For this reason, researchers are developing cuffless alternatives with the goal of unlocking new possibilities for patient diagnostics and management, as well as providing new understanding of physiology. However, none of these tools has become a mainstay yet.

One option, acoustic sensors, slide during movements and are too large to be easily incorporated into untethered ambulatory sensors. Meanwhile, optical modalities such as smart watches are limited by the low penetration of light into tissues, which hinders their ability to capture haemodynamic parameters in the arteries. Studies also show that optical sensors are sometimes inaccurate when used with darker skin tones or larger wrists.