At one time or another we’ve all sat on a long plane ride, been confined to bed for several days, or been immobile after surgery. These situations can put us at increased risk for life-threatening blood clots.

There is currently no quick or easy way to detect clots. Often, they are diagnosed only after causing a stroke or heart attack. But now, a simple, noninvasive urine test for clot detection is being developed.

A team of MIT engineers has designed the test, described in a recent issue of the journal ACS Nano, using nanoparticles to detect the presence of thrombin, a key blood-clotting factor. Such a system could be useful to monitor patients who are at high risk for blood clots.

“Some patients are at more risk for clotting, but existing blood tests are not consistently able to detect the formation of new clots,” says Sangeeta Bhatia, senior scientist on the project and the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical Engineering and Computer Science, also a senior associate member of the Broad Institute and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

Bhatia envisions two applications for this test. One is to screen patients who come to the emergency complaining of symptoms that might indicate a blood clot. This new diagnostic test would allow doctors to rapidly triage such patients.

“Right now they just don’t know how to efficiently define who to do the more extensive workup on. It’s one of those things that you can’t afford to miss, so patients can get an unnecessarily expensive workup,” Bhatia says.

A second application would monitor patients at high risk for a clot. Bhatia and her team are working on a urine dipstick test, similar to a pregnancy test, that doctors could have patients take home after surgery.  “If a patient is at risk, you could send them home with a 10-pack of these sticks and say, ‘Pee on this every other day and call me if it turns blue,’” she says.

Henri Spronk, an assistant professor of biochemistry at Maastricht University in the Netherlands, sees an additional application for this technology: predicting the recurrence of clots. “Through application of the nanoparticles, if proven well-tolerated and nontoxic, alterations in the normal low levels of physiological thrombin generation might be easily detected,” says Spronk, who was not part of the research team.