Medical advances don’t have to be dramatic. Even small changes can save lives. Take an app that uses an iPhone camera to determine if an artery is healthy enough to accept the catheter needed to restore blood flow to a patent’s heart. It’s still experimental, but is significantly better than the current method.

A simple test is usually performed to see if an artery is up to a catheter: all blood flow to the hand is blocked by applying pressure until the skin turns white. Next, pressure is removed from one of the arteries leading to the hand while a doctor looks to see if the palm’s normal color is restored. This is called the Allen test.

A new testing method

Hoping for a better method, researchers checked to see if an iPhone’s camera would be more accurate at determining whether the hand had proper circulation. They used an app for photoplethysmography (using a camera to detect blood flow) on the patient’s index finger.

The researchers used iOS software that’s not available yet. It’s still undergoing testing before release. The device was an iPhone 4.

All the patients in this experiment underwent both these methods to see how healthy their arteries were. Then an doppler ultrasonography was done on the arteries to truly determine how much blood they were allowing to flow. This is a more time consuming and expensive test than the other two.

A better solution

The researchers found that the iPhone was 91.8 percent accurate, while the Allen test was 81.7 percent accurate.

“Using a smartphone to monitor changes in color in the fingertips is much more accurate in detecting subtle changes as opposed to the doctors’ general opinion of the color of the hand,” Dr. Benjamin Hibbert of the University of Ottawa Heart Institute in Canada, and the senior researcher in this study, told Reuters.

Using smartphones and smart watches as medical diagnosis devices is becoming increasingly common. The next Apple Watch might have built-in a blood pressure monitor, for example.