The aim of this note is to report experimental results obtained for mass transport under controlled flow conditions in a system where convection and diffusion are coupled with chemical interactions associated to the protein adhesion. The context of the problem is of crucial practical importance in the framework of medical application and is concerned with the maintenance of central venous catheters. Then a phenomenological description is suggested giving a possible description of the process. Crown Copyright (C) 2011 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.