Scientists at the University of Washington (UW) have created a simple, disposable test for malaria that could prove particularly valuable in countries that lack reliable health care.

What separates this test from others like it is that the reacting proteins used can withstand warm temperatures for long periods. Usually reagents must be refrigerated in order to work, which presents a huge barrier to developing tests for places that lack steady electricity. Paul Yager, a professor of bioengineering at UW, and his colleagues dried antibodies with sugar in a way that allowed them to survive for over two months in warm temperatures.

Tiny channels inside the credit-card-size device direct a patient’s blood sample to testing sites where antibodies bind to malarial proteins, creating colored spots that a portable, automated reader (dubbed the DxBox) interprets.

With funding from the Gates Foundation, the team plans to collaborate with other groups, including Micronics, Nanogen, and PATH, to create more cards that can test for other diseases, including the flu and the measles. Other groups are trying to develop cheap and compact diagnostic tests for everything from cancer to heart attacks. But this seems like an impressive step toward a small, rugged test that could remain reliable and accurate even in harsh conditions.