Most countries, including the U.S., lack integrated online patient-record systems. Patients visiting new doctors need to fill out paper medical-history forms. What's more, over time, records can become spotty, incomplete, and difficult to access. This leads to both inefficiencies in the medical-record system, which cost money, and medical mistakes, which can cost lives. Researchers and entrepreneurs hope to change that by giving each patient a smart card containing his or her complete medical history. This approach may prove difficult to implement in the U.S., owing to security fears and compatibility issues, but the technology has the potential to transform health care in countries that have unified health systems, or where there's inadequate infrastructure for sharing records in other ways. Researchers in the U.K. have developed the MyCare card, which is roughly the size and shape of a credit card, with a fold-out USB plug. Another project, SmartCare, first implemented in Zambia, has recently expanded to Ethiopia and South Africa and demonstrates the potential for card-based systems in parts of the world with limited infrastructure.