The novel tool is so small that it can be easily slipped into a wallet, and can work even when taken out months later.

The prototype developed by Paul Yager, UW bioengineering professor, and colleagues, dehydrated the reagents to store them without refrigeration, and delivered a diagnosis in just nine minutes.

The cards are a critical step in a long-term project funded by The Bill and Melinda Gates Foundation’s Grand Challenges in Global Health Initiative to develop affordable, easy-to-use diagnostic tools for the developing world.

"A pivotal issue in having this technology work is making these tests storable for long periods of time at ambient temperatures. Normally people work with wet reagents. We’re saying we can dry the reagents down in order to store them without refrigeration. It’s the astronaut-food approach," said Yager.

The malaria cards contain reagents that would normally require refrigeration, but the researchers stabilized them in dry form by mixing them with sugar.

The long-term project is aimed at developing a system with which a clinician can spot a drop of a patient’s blood onto a card, and feed it into an instrument that gives a yes/no answer for a panel of infectious diseases in 20 minutes or less.

While treatments in poor, rural communities come with their own difficulties, diagnosis is the key to getting good medical care, said one of the researchers on the study.

The malaria-test card is being developed as part of an automated diagnostic system informally called the DxBox, the Dx being medical shorthand for diagnosis.

The DxBox consists of a portable, fully automatic reader being developed by Micronics that will process the card-based disposable tests.

The UW prototype cards look for the presence of malarial proteins and use features of common lab tests and take into account portability, automation and easy storage.

The cards rely on microfluidics- the manipulation of liquids at very small scales. Thin channels crisscross the Mylar sheets, and syringes are used to pump different liquids for the tests through the channels.

The DxBox works by detecting the coloured spots on the card that indicate the presence of malaria proteins.

The researchers are working towards cards that also will test for five other diseases that, like malaria, cause high-fever symptoms: dengue, influenza, Rickettsial diseases, typhoid and measles.