Smartphone app can detect how well blood clots with a single drop of it, finds study 

Washington [US], February 13 : Blood clots form naturally as a way to stop bleeding when someone is injured. A team of researchers at the University of Washington developed a new blood-clotting test that used only a single drop of blood and a smartphone vibration motor and camera. The system included a plastic attachment that holds a tiny cup beneath the phone's camera.

The team published their findings in 'Nature Communications'.

Blood clots in patients with medical issues, such as mechanical heart valves or other heart conditions, can lead to a stroke or heart attack. That's why millions of people take blood-thinning medications, such as warfarin, that make it harder for their blood to clot.

Warfarin however, requires patients to be tested frequently to make sure their blood is in the correct range -- blood that clots too easily could still lead to a stroke or a heart attack while blood that doesn't clot can lead to extended bleeding after an injury. To be tested, patients either have to go to a clinic laboratory or use a costly at-home testing system.

In the new blood clotting test, a person adds a drop of blood to the cup, which contains a small copper particle and a chemical that starts the blood-clotting process. Then the phone's vibration motor shakes the cup while the camera monitors the movement of the particle, which slows down and then stops moving as the clot forms. The researchers showed that this method falls within the accuracy range of the standard instruments of the field.

"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 infeasible to use in home settings," said senior author Shyam Gollakota, UW professor in the Paul G. Allen School of Computer Science & Engineering. "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."

Doctors can rank blood-clotting ability using two numbers: first, the time it takes for the clot to form, what's known as the "prothrombin time" or PT and second, a ratio calculated from the PT that allows doctors to more easily compare results between different tests or laboratories, called the "international normalized ratio" or INR.

"Most people taking this medication are taking it for life. But this is not a set-and-forget type of thing -- in the U.S., most people are only in what we call the 'desirable range' of PT/INR levels about 64 per cent of the time," said co-author Dr. Kelly Michaelsen, assistant professor of anaesthesiology and pain medicine in the UW School of Medicine. "This number is even lower -- only about 40 per cent 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."

Patients who can monitor their PT/INR levels from home would only need to go to see a clinician if the test suggested they were outside of that desirable range, Michaelsen said.

( Details and picture courtesy ANI, the content is auto-generated from feed.)

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