Can the most modern of technologies help solve the health woes in the poorest countries in the world? Some biomedical engineers say yes. They are designing diagnostic laboratories that fit on something as small as a credit card, and give results in minutes instead of hours or days. These devices are sometimes referred to as a "lab on a chip." To use them, all you need to do is obtain a drop of someone's blood. "The drop of blood goes into the chip, and you wait about 15 minutes, and you will get the results," says Samuel Sia, a professor of biomedical engineering at Columbia University in New York. Inside the chip are tiny channels that expose the blood to chemicals that can detect diseases. If a disease is present, a dark line will appear in a window on the chip. Not only is the test portable, it's relatively cheap. The chip itself is only 10 to 20 cents. The cost goes up once you add in the chemicals you need and the appropriate packaging, but "we think we can do it for $2 to $3 dollars per chip, and that would include the ability to diagnose multiple diseases on one card," he says.