The move towards mobile medicine is pretty incredible in a few different ways. For one, it offers an aging population — in the U.S. it’s the baby boomers — an option for treatment that doesn’t involve more doctor’s offices or hospitals than necessary. On the other hand, mobile medicine provides a great way to offer better healthcare in very poor or very remote areas of the U.S. and around the world.

Because mobile phones are widely available (or at the very least can be easily acquired) in most countries, apps are playing a big role in this movement. A new app, called The Phone Oximeter and created by LionsGate Technologies, is designed to track blood oxygen levels via a light sensor that can be attached to the patient’s finger. Once the rapid diagnosis is complete, the app can guide diagnosis and management of the problem.

The diagnostic method is called pulse oximetry and it measures the proportion of hemoglobin (oxygen carrying molecules) that are actually carrying oxygen. Traditionally, machines used to test this would shine infrared and red light through the blood in the finger. Hemoglobin with oxygen absorbs infrared while red light passes through it. Hemoglobin without oxygen allows more infrared to pass through.

Why is this number important? The amount of oxygen in your blood can play a key role in the diagnosis and treatment of a number of diseases that affect a lot of people. The device could play a big role in reducing the maternal and infant death rate caused by preeclampsia (high blood pressure).

Preeclampsia kills 76,000 of the 10 million pregnant women diagnosed annually and is the second leading cause of maternal deaths. It also causes 500,000 infant deaths. The challenge is that many of these deaths take place in remote areas without access to traditional diagnostic machines. In fact, an estimated 99 percent of deaths occur in developing countries. The app, priced at $40, can accurately identify 80 percent of the cases and allow medical professions to intervene.

The app can also be used to diagnose pneumonia, which kills more than one million children every year.

It’s an exciting development—and a cheap price—for the medical world. The app is scheduled for a trial run for 80,000 women in India, Pakistan, Namibia and Mozambique.