Few experiences invoke as much anxiety as a call from your doctor saying "you need to come back for more tests." Your imagination goes wild and suddenly a routine medical screening becomes a minefield of potential life-threatening diseases.

It's highly likely, however, that you have fallen victim to a false positive—a result that, despite the accuracy of the test, erroneously yields an affirmative result that points toward illness. Statistically, there's usually not much cause for alarm. But tell that to the person who has to undergo additional blood draws, invasive tests or even therapies. While the result is false, the psychological toll is real, and so are the billions of dollars spent every year on tests and procedures performed as a result of false positives.

"There are these horror stories," said UC Santa Barbara researcher Tracy Chuong. "Usually they go in for second opinions, get another test and it turns out to be a big scare. But it does cost the healthcare system quite a bit of money."

To increase the accuracy of medical screening and reduce the incidence of false positives, Chuong, along with UCSB chemistry and biochemistry professors Martin Moskovits and Galen Stucky and Stanford chemical engineering professor Tom Soh, designed a biomedical assay that eliminates the readout of these faulty results. Not only does the assay provide greater accuracy, it reduces the wait time for results. It is an improvement on the popular enzyme-linked immunosorbent assay (ELISA), which detects concentrations of proteins that correlate with conditions from pregnancy to allergies, to infectious disease.