With a simple tube, some software and a saliva sample, people and
their doctors can measure levels of the stress hormone cortisol,
according to new research presented last week at ICE/ENDO 2014, the
joint meeting of the International Society of Endocrinology and the
Endocrine Society in Chicago.
"We have designed a method by which anyone with a smartphone will be
able to measure their salivary cortisol level quickly, easily and
inexpensively," said lead investigator Dr. Joel Ehrenkranz, director
of diabetes and endocrinology at Intermountain Healthcare in Murray,
While a commercial lab in the United States may charge up to $50 to
run a quantitative salivary cortisol test and take up to a week to
provide the results, the smartphone test will cost under $5 and give
results in less than about 10 minutes, Ehrenkranz told Reuters
Health in an interview.
"Parts of the United States and the rest of the world that lack
facilities to measure cortisol will now be able to perform this
essential diagnostic test,” he said. “Also, measuring salivary
cortisol with this technology will provide a way for individuals to
monitor their personal biometric stress levels easily and
Ehrenkranz and his research team would like to see healthcare
providers around the world, especially in low-resource areas, use
the smartphone test to help diagnose disorders involving excessive
cortisol or depletion of the hormone, and to allow cortisol levels
to be monitored easily over time.
They’d also like the public to monitor their own cortisol levels
whenever they want. So they designed their device to be inexpensive
to manufacture, and easy to use on all cell phones, all platforms
and all form factors.
It consists of a case, a light pipe, and a lens, it uses no battery
power and it’s unbreakable and reusable, they say.
For the developing world, it needs to be inexpensive, Ehrenkranz
said, and it costs only about $1 to make.
Project collaborator Dr. Randall Polson, senior optical engineer in
the College of Engineering at the University of Utah in Salt Lake
City, wrote in an email, "We are trying to make sure a skilled
8th-grader – a 12-year-old – can get accurate results."
"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, so if
you have a charged phone and a test kit you can get accurate results
without complicated infrastructure and highly trained technicians,"
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To take the test, a person puts a straw-like saliva collector under
the tongue, and capillary action wicks the saliva to an assay strip
in a cassette that's inserted into a reader; the reader aligns a
lens and light diffuser with a smartphone’s camera and flash. A few
minutes later, the smartphone image analysis app quantifies the
The abstract for the team’s June 24 presentation is online here:
Dr. Ehrenkranz said the first screening test for hypercortisolism is
salivary cortisol, and that 3 percent of people with type 2 diabetes
actually have Cushing's disease - of which excess cortisol would be
a sign - but they don't get screened because their doctors don't
have access to the technology.
It will also help individuals, Ehrenkranz said. As an example, he
cited the 10 percent of people with depression who have psychotic
depression, with cortisol levels that rise before the onset of
psychosis. Using this device, people at risk for psychotic
depression will be able to check their salivary cortisol level every
day and take steps to avoid a psychotic break.
The Ministry of Public Health of Thailand plans to introduce the
cortisol test later this year, as a consumer product to monitor
individuals’ stress, Ehrenkranz said. His team is collecting
clinical data to submit to the FDA to gain approval to market the
test as a class 2 medical device, which they hope will be granted in
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