The lock device has lock portion (43) with proximal and distal ends. The distal and proximate ends are arranged inside and outside patients body respectively. A tubular portion (41) and valve are arranged at proximal end of lock casing which is provided with receiving channel (46) for catheter. The tubular portion is releasably retained to a clamping device (45,48,50) in the lock casing. Independent claims are included for the following: (1) catheter system and (2) method for insertion of catheter into patient body.
