Smartphone apps continue to find new purposes, including testing people for sexually transmitted diseases (STDs).

The app, created by a group of engineers at Columbia University, has already been tested in Rwanda, where there are a large number of pregnant women who pass down STDs to their unborn children, according to CBS News.

Samuel K. Sia, an associate professor of biomedical engineering at Columbia University and leader of the research team, said they can diagnose and treat pregnant mothers early to reduce the risk of death for mothers and their babies by increasing detection of syphilis and HIV, which the World Health Organization says are among the top diseases needed in portable blood tests for pregnant women.

The team's diagnostic dongle works with both iOS and Android phones, plugging into the headphone jack so people can conduct tests in remote areas, CBS News reported.

The process include collecting three markers, one for HIV and two for syphilis, by pricking the patients finger in a traditional STD test called an enzyme-linked immunosorbent assay (ELISA), Fox News reported.

While it normally takes days for traditional laboratory tests in the U.S. and around the world to deliver results, the smartphone dongle can do so in only 15 minutes.

The device had a high success rate in a pilot study involving 96 pregnant women, with researchers finding a 92-100 percent accuracy rate for tests that were true-positive and a 79-100 percent accuracy rate for tests that were true-negative.

Investors in the dongle believe the device could change the way diagnostic tests are done in the U.S. and other developed countries, Fox News reported.

"In the U.S. actually, there's a trend towards providing a lot of health care services away from hospitals- it's infrastructure-heavy and expensive, and you really shouldn't have to be there," Sia said. "Catching diseases is about being proactive and preventative ... [with these accessories] I think you could actually see a lot of savings, and more privacy and convenience."

The dongle also saves money, costing only $34 to make while ELISA equipment normally costs about $18,450.

Sia said the team hopes to use the dongle to test for more than just STDs, such as cancer, diabetes and other diseases, and that the shift to portable health devices will improve the way future tests are done.

"What we're trying to offer here is going beyond these accelerometers which track your movement," he said. "I think that's when you'll see the health care system fundamentally transformed for the better."

The study was published Wednesday in the journal Science Translational Medicine.