To establish a standardized method for the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsored research in the Integrated Islet Distribution Program (IIDP) for preparing a sentinel flask of human islets in order to monitor sterility and islet integrity at the production center. This is a representative sample of the islet preparation that has been distributed to investigators and is held at the distributing center as a quality control sample. The islets are cultured in the same shipping media used for islet shipment, for 18 hours at 4-8°C, simulating the cold shipping conditions followed by 2 days at 37°C culture. The flask of islets are verification in the event of a dispute over sterility or islet quality.