Abstract
Practice Fusion is a free, web-based electronic health record system with over 150,000 medical professional users treating over 50 million patients. Its large user base, with representation in all 50 states, makes it an ideal system for public health surveillance. The company''s Research Division has undertaken pilot studies to demonstrate the viability of surveillance for acute diseases, like influenza-like illness, chronic diseases, like diabetes, and risk factors, like hypertension. Comparisons to the CDC have proved the data to be a reliable foundation for public health surveillance.