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SprioSmart app lets phone accurately measure lung capacity

Shwetak Patel tests the SpiroSmart app out. S. Patel, Univ. of Washington

(CBS News) Want to test your lung capacity? There may be an app for that.

SprioSmart uses a smartphone's microphone to take lung measurements of breath capacity. For people with pulmonary problems like asthma, chronic obstructive pulmonary disease and cystic fibrosis, this easy to use method may be a game changer.

"There's a big need in the pulmonary community to make testing cheaper and more convenient," said lead researcher Shwetak Patel, a University of Washington assistant professor of computer science and engineering and of electrical engineering, in a  press release. "Other people have been working on attachments for the mobile phone that you can blow into. We said, 'Let's just try to figure out how to do it with the microphone that's already there."

Currently, there are home testing systems known as spirometers that patients can purchase but they range in cost from a few hundred dollars to a few thousand dollars. They work by having patients breathe into a tube that contains a turbine so the machine can measure the speed of the breath flow. This tells doctors how a patient's airways are restricted or filled with mucous.

But a downside is a person who needs to measure their air flow frequently would have to carry around the device. There are also other smartphone apps, but none of them are currently recommended for medical use.

The new app is also not FDA-approved but the team of researchers is seeking approval.

To produce the app, the team created an algorithm that replaced the tube and turbine with a persons trachea and vocal tract, and then used the iPhone's microphone to check the sound wave frequencies from a person's breath.

Researchers tested the program on 52 mostly healthy subjects using an iPhone 4S, and found that the SpiroSmart app had a 5.1 percent error rate compared to a clinical spirometer, and is well within the guidelines of a 5 to 7 percent error rate set by the American Thoracic Society.

Ideally, Patel told TechNewsDaily that he hopes physicians can prescribe the app to their patients, who can then administer the tests themselves using their phones. Then, the results can be sent directly to the doctors for analysis. He also hopes another version not linked to the doctor's office can be created for people just curious about their breath capacity.

To see the app in action, check out the video below:

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