Most blood tests require shipping vials off to a lab, followed by several days of nail biting. This kit, one of the first that can diagnose multiple diseases on the spot, shrinks an entire lab into a two-piece portable package that even novices can use. A disposable, $1 plastic card, formed through injection molding, holds miniature versions of test tubes and chemicals. In place of technicians or $100,000 machines, a battery-powered, $100 gadget mixes the molecules. The prototype, from Claros Diagnostics and Columbia University bioengineer Sam Sia, is currently being tested in Rwanda, where potentially lethal diseases like HIV/AIDS often go undetected. Sia's latest study estimates that global access to a low-cost test for syphilis, for example, could prevent a million stillbirths a year. "In the U.S., point-of-care devices like this are attractive because they are more convenient," he says. "In developing countries, there is simply no alternative."