(Reuters Health) - A next step in wearable health sensors might be a device that causes a patch of skin to sweat, then analyzes the perspiration to monitor or even diagnose disease.
Researchers used a prototype to extract sweat from volunteers with the lung disease cystic fibrosis, measure specific compounds that are signatures of the disease, then transmit the data wirelessly for further analysis.
They did a similar experiment to see if sugar levels in sweat rose in tandem with blood sugar.
“With the technology that we’ve made use of we could really move faster into personalized care by using devices that can allow for real-time monitoring,” study coauthor Dr. Carlos Milla of Stanford University in California told Reuters Health. “There’s a large number of things that you can measure in sweat that can be very valuable.”
While sweat testing offers a “noninvasive and rich source of information,” Milla and his team write in the Proceedings of the National Academy of Sciences, the difficulty of collecting adequate amounts of sweat in sedentary individuals has limited its usefulness in cystic fibrosis (CF) diagnosis.
Presently, CF testing must be done in certified labs, in a two-step process that takes hours and typically requires two technicians. The prototype consists of an interface that stimulates sweating then draws the sweat, integrated with an analysis platform. It can do the job in a single step, without causing discomfort to the patient, the researchers write. Readings can be transmitted via smartphone for review by a specialized center, which transmits results back to the phone.
In their experiment, the researchers tested the device in six healthy individuals and three CF patients to measure levels of sodium and chloride in sweat. The healthy volunteers had normal sodium and chloride levels while levels in the individuals with CF were about four times higher.
The investigators also tested sweat glucose levels in seven healthy individuals who consumed 30 grams of oral glucose after fasting. In six of the study subjects, sweat glucose levels rose along with glucose levels in the blood.
Using the device to test sodium and chloride in sweat currently takes about half an hour, Milla noted, and the researchers are working to speed up the process. They are also planning large studies to investigate how sweat-sensor readings correlate with health.
“Our solution opens the possibility for a broad range of noninvasive diagnostic and general population health monitoring applications,” the researchers conclude.
SOURCE: bit.ly/2oPuHf0 Proceedings of the National Academy of Sciences, online April 17, 2017.