 The majority of data acquired in this study originates from electronic sources. Screening data and symptoms entered via the smartphone are immediately transferred over an encrypted channel to the server and stored in a MySQL-database. Both the server application and the database are hosted on a professional application hosting provider located in Switzerland. The server application and the database design are developed and tested by Gastric Imaging Analysis GmbH. The software version used during this study will be tested using semi-automated functional tests and load tests. Study principal investigator Mark Fox is responsible for all data stored in the database. 