ISO 13958:2009 specifies minimum requirements for concentrates used for haemodialysis and related therapies. For the purpose of this International Standard, “concentrates” are a mixture of chemicals and water, or a mixture of chemicals in the form of dry powder or other highly concentrated media, that are delivered to the end user to make dialysis fluid used to perform haemodialysis and related therapies.

ISO 13958:2009 is addressed to the manufacturer of such concentrates. In several instances in this International Standard, it became necessary to address the dialysis fluid, which is made by the end user, to help clarify the requirements for manufacturing concentrates. Because the manufacturer of the concentrate does not have control over the final dialysis fluid, any reference to dialysis fluid is for clarification and is not a requirement of the manufacturer.

ISO 13958:2009 includes concentrates in both liquid and powder forms. Also included are additives also called spikes, chemicals which may be added to the concentrate to increase the concentration of one or more of the existing ions in the concentrate and thus in the final dialysis fluid. This International Standard also gives requirements for equipment used to mix acid and bicarbonate powders into concentrate at the user's facility.