<p>A porous polymeric medium having a low affinity for amide group-containing materials is provided comprising a porous polymeric substrate and a surface-modifying polymeric material having a low affinity for amide group-containing materials formed in situ and covalently bonded to the surface of the porous polymeric substrate, the surface-modifying polymeric material being formed from a monofunctional monomer having at least one hydroxyl group.</p>