A catheter assembly is disclosed comprising: a hydrophilic catheter a wetting fluid for wetting of the catheter and a receptacle enclosing at least the insertable part of the catheter and the wetting fluid. Further, the wetting fluid is a solution incorporating at least one osmolality-increasing compound, and the total concentration of the osmolality-increasing compound(s) is very high, preferably exceeding 600 mOsm/dm3. The wetting fluid could either be arranged in contact with the hydrophilic surface layer of the catheter in the receptacle, for preservation of the hydrophilic surface layer in a wetted state during accommodation in said receptacle and provision of a ready-to-use catheter assembly, or be arranged to keep the wetting fluid separated from the hydrophilic surface layer of the catheter during storage, but to be brought into contact with said hydrophilic surface layer upon activation before an intended use of the catheter. A similar method and wetting fluid is disclosed as well. The provision of the osmolality-increasing compound in the wetting fluid provides several advantages per se, such as a improved properties of the hydrophilic coating, a more predictable and controllable wetting process, a more expedient and cost efficient production, etc. Further, the use of this very high concentration of osmolality-increasing compound in the wetting fluid has proven remarkably efficient.
