Three methodologies are presented to contemplate the analysis of sodium, potassium, chloride, bicarbonate, lactate, acetoacetate, and beta-hydroxybutyrate in blood serum samples of diabetic patients using free solution capillary electrophoresis with indirect detection (214 nm for cations and 254 nm for anions). The cations were analyzed in less than 6 min in an electrolyte comprised of 15 mmol(.)L(-1) imidazole, 5 mmol(.)L(-1) lactate and 1 mmol(.)L(-1) 18-crown-6-ether, adjusted to pH 4.5. Chloride and bicarbonate were analyzed in 2 min in a 5 mmol(.)L(-1) chromate, 0.1 mmol(.)L(-1) cetyltrimethylammonium bromide (CTAB), pH 9.0 electrolyte solution. Ketoacids and lactate were analyzed in less than 11 min in an electrolyte composed of 15 mmol(.)L(-1) 3,5-dinitrobenzoate, 0.1 mmol(.)L(-1) CTAB, at pH 3.5. All methodologies were validated with respect to linearity, selectivity, sensitivity, precision and accuracy performing adequately for clinical purposes.