Typing the word "stress" in the App Store research bar produces a multitude of apps oriented towards detecting and reducing stress, most of which are presented as lighthearted distractions. Now scientists have created a device that tests the levels of the stress hormone cortisol in saliva and presents results on smartphones.
"We have developed a method for measuring cortisol in saliva using a smartphone and a disposable test strip," says says lead study author Joel R. L. Ehrenkranz, MD, director of diabetes and endocrinology of the Department of Medicine at Intermountain Healthcare in Murray, Utah. "This innovation enables anyone with a smartphone to measure their salivary cortisol level quickly, accurately, and affordably."
Cortisol is produced by the adrenal glands and is an indicator of stress or glandular dysfunction.
Current testing methods use saliva samples, which are analyzed in a clinical laboratory. According to Dr. Ehrenkranz, laboratory tests for cortisol levels in the United States run between $25 and $50 and take at least a week to process.
Testing using the device, he says, will cost no more than $5 and results become available in 10 minutes.
Dr. Ehrenkrantz and his team are preparing to submit approval requests to the FDA, which could be granted as early at 2015.
Testing involves the insertion of a plastic saliva collector under the tongue that wicks the fluid to a biochemical testing strip housed in a cassette.
The cassette is then inserted into a reading machine and the smartphone takes a flash photo of the strip.
The pixel density of the image is the determining factor, and this is converted by means of algorithms to measure cortisol content.
According to Dr. Ehrenkranz, the unbreakable, reusable device includes a case, a light pipe, and a lens, and production costs are about $1 per unit.
The device works on all platforms, including iOS, Android, Windows, and BlackBerry, and it has a universal form factor that works with all smartphones.
It was presented Tuesday, June 24, at ICE/ENDO 2014, the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago.