A method for ensuring that sensitive data stored in a first storage medium (206, 208, 504) of a portable device are not accessible to unauthorized persons, the sensitive data comprising patient data, the sensitive data stored in the first storage medium being modifiable by a user, wherein the sensitive data is also stored on a second storage medium coupled to a server, the method comprising: - continuously synchronizing the sensitive data stored in the first storage medium on the portable device and the sensitive data stored in the second storage medium; - the portable device determining its current position (106, 116); - the portable device determining if its current position lies within a predefined security perimeter surrounding an analyzer of an analysis system; - the portable device requesting the sensitive data from a data source (120, 112), the data source being a pre-analytical, analytical or post-analytical lab-device or a laboratory information system, the sensitive data comprising measurement data, monitoring data and/or status information received from the lab device, whereby the portable device requests the sensitive data only if its current position lies within the security perimeter at the moment of request submission; and - receiving the requested sensitive data from the data source by the portable device; - continuously repeating the determining of the current position, whereby in case the current position is determined to lie outside the security perimeter, the portable device automatically erasing the sensitive data from the first storage medium; - in case the current position is determined to lie outside the security perimeter, and in case in addition the user has appropriate privileges, accessing, by the user, the sensitive data stored in the second storage medium directly via a network connection between the portable device and the server. - continuously synchronizing the sensitive data stored in the first storage medium on the portable device and the sensitive data stored in the second storage medium; - the portable device determining its current position (106, 116); - the portable device determining if its current position lies within a predefined security perimeter surrounding an analyzer of an analysis system; - the portable device requesting the sensitive data from a data source (120, 112), the data source being a pre-analytical, analytical or post-analytical lab-device or a laboratory information system, the sensitive data comprising measurement data, monitoring data and/or status information received from the lab device, whereby the portable device requests the sensitive data only if its current position lies within the security perimeter at the moment of request submission; and - receiving the requested sensitive data from the data source by the portable device; - continuously repeating the determining of the current position, whereby in case the current position is determined to lie outside the security perimeter, the portable device automatically erasing the sensitive data from the first storage medium; - in case the current position is determined to lie outside the security perimeter, and in case in addition the user has appropriate privileges, accessing, by the user, the sensitive data stored in the second storage medium directly via a network connection between the portable device and the server.