The allergy problems described with these membranes require the development of other membranes capable of performing this treatment. We describe in vivo performance and behaviour of an asymmetric cellulose triacetate(ATA™) membrane, to identify its depurative effectiveness and ease of use in clinical practice, as well as evaluate its biocompatibility in a single haemodialysis session (acute biocompatibility) and after one month of treatment (chronic).