ISO 13958:2014 specifies minimum requirements for concentrates used for haemodialysis and related therapies. For the purpose of ISO 13958:2014, "concentrates" are a mixture of chemicals and water, or 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 13958:2014 is addressed to the manufacturer of such concentrates.

ISO 13958:2014 includes concentrates in both liquid and powder forms. Also included are additives, also called spikes, which are chemicals that 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. ISO 13958:2014 also gives requirements for equipment used to mix acid and bicarbonate powders into concentrate at the user's facility.