Phone app that measures blood clotting could prevent millions of heart attacks

By Tom Campbell via SWNS

An app that uses mobile phone vibrations to measure blood clotting could prevent millions of potentially fatal heart attacks.

The technology offers people taking heart medication a much cheaper way of monitoring their blood's thickness, say scientists.

While blood clots form naturally to prevent bleeding when someone is injured, they can also prove fatal for patients with heart conditions.

Those fitted with a mechanical heart valve could especially be at risk of suffering from a stroke or heart attack if their blood thickens.

This is why millions of people living with heart problems around the world rely on blood thinning tablets like warfarin to prevent it from clotting.

But maintaining the right thickness level is tricky and requires patients to get tested on a regular basis, either at a medical clinic or using an expensive home testing kit.

Now researchers in the United States have come with a much 'smarter' solution using a mobile phone.

Senior author professor Shyam Gollakota at the University of Washington said: "Back in the day, doctors used to manually rock tubes of blood back and forth to monitor how long it took a clot to form.

"This, however, requires a lot of blood, making it unfeasible to use in home settings."

Their new system holds a tiny cup beneath the phone's camera which contains a small copper particle and chemical to start the blood-clotting process.

Once a drop of blood has been added, the phone's motor vibrates, shaking the cup while the camera tracks the particle's movements.

As the blood becomes increasingly thick, the particle slows down and eventually stops once a clot has formed.

The phone then records two timestamps, one when the drop of blood is added and the second when the particle stops moving.

This way it can measure the time it takes for blood to clot, which is either measured by what's known as prothrombin time (PT) or an international normalized ratio (INR).

Professor Gollakota said: "The creative leap we make here is that we're showing that by using the vibration motor on a smartphone, our algorithms can do the same thing, except with a single drop of blood.

"And we get accuracy similar to the best commercially available techniques."

Their new technology could help millions of people who rely on blood thinning meds like warfarin keep an eye on their clotting abilities.

Co-author Dr. Kelly Michaelsen said: "Most people taking this medication are taking it for life.

"But this is not a set-and-forget type of thing - in the US, most people are only in what we call the 'desirable range' of PT/INR levels about 64 percent of the time."

There are around 100,000 strokes in the UK every year, and some 7.6 million people are living with a heart or circulatory disease.

Dr. Michaelsen said: "This number is even lower - only about 40 percent of the time - in countries such as India or Uganda where there is less frequent testing.

"How can we make this better?

"We need to make it easier for people to test more frequently and take ownership of their health care."

By using their technology, patients would only need to visit a clinic if their results were outside the desirable range.

Their device was tested on three different types of blood sampled from 140 anonymized patients at the University's medical center.

They also examined 79 blood samples from patients with known blood clotting issues and found the results were equivalent to other commercially available tests.

While the device is still in a proof-of-concept stage, the researchers have made the app's code and are exploring next steps.

They would like to further test the system in people's homes and in countries with fewer resources.

Professor Gollakota said: "Almost every smartphone from the past decade has a vibration motor and a camera.

"This means that almost everyone who has a phone can use this. All you need is a simple plastic attachment, no additional electronics of any kind.

"This is the best of all worlds - it's basically the holy grail of PT/INR testing."

The findings were published in the journal Nature Communications.