A few years ago, people use their mobile phones only for calls and text messages. But with the continued advancements in mobile phone technology, it is now common to see smartphones that can take photos, record videos and allow users to access the Internet while on the go.

While the features that are found in many smartphones today are already more than enough, it appears that smartphones are still on for more improvements and some will benefit individuals with certain health conditions. A group of researchers said that smartphones may soon be able to measure a person's stress level.

For their study presented at the International Society of Endocrinology and the Endocrine Society in Chicago joint meeting on June 24, Joel Ehrenkranz, from the Department of Medicine at Intermountain Healthcare in Murray, Utah, and colleagues said that they have come up with a smartphone-based test that can measure levels of the stress hormone cortisol using a saliva sample, software and a simple tube.

"We have developed a smartphone-based quantitative salivary cortisol immunoassay that provides results in 5 minutes and can be performed at the point of care," the researchers reported

Certain individuals need to have their cortisol levels monitored including those who have risks for psychotic depression, where an increase in salivary cortisol levels could mean an onset of their condition.

One problem with current stress hormone tests is that it takes a while before the results become available. Turnaround time for lab test results can be as long as a week but results of the smartphone-based test are available in as little as 10 minutes. While laboratories charge $25 to $50 for a salivary cortisol test, Ehrenkranz said that the smartphone based test will cost cheaper at less than $5.

The device consists of a case, lens and light pipe and can be used on all smartphone platforms, which means that it will work on smartphones running on iOS, Android, Windows and BlackBerry.

Randall Polson, from the University of Utah College of Engineering, explained how the mobile cortisol test works.

"The measurement system's smartphone and reader act as a photo studio. . . . The complex and difficult processes are put into the strip chemistry and embedded into the smartphone application," Polson said.

Ehrenkranz and colleagues said that they are in the process of collecting clinical data that they will submit to the Food and Drug Administration to gain approval for the marketing of the device.