Abstract: A multi-purpose blood diluent for blood cells for use in electronic counting and sizing of blood cells comprising a stable water solution of chemical salts providing an electrolytic solution to which a blood sample can be added to dilute the large number of red blood cells, white blood cells and other components and enable the desired parameters of these blood components to be measured, counted and determined. The diluent is azide-free and contains a bacteriostatic agent that substantially reduces the bubble formation capable of interfering with the determinations that resulted from the prior art use of 2-phenoxyethanol as the bacteriostatic agent. The diluent employs phenylethanol as the bacteriostatic agent and lithium chloride as the agent to stabilize red blood cell volume.