Abstract: | The measurements of intracellular "Na+ activity" was performed in 10 ml of heparinized venous blood. First the blood was three times washed in isotonic magnesium chloride solution (114 mmol/l). Thereby the buffy coat was removed. Then the microhematrocrit was taken for packet cell volume determination. After the erythrocytes were lysed by ultrasound. Sodium "Na+ Activity" is measured in the hemolysate by Ion-Selective electrode. With this method all "pipetting" operations are eliminated and for the "Na+ activity" determination was used ion-selective electrode with an indirect measurements, which is less influenced by the matrix. Reference intervals determined for a healthy population were 7.3 +/- 0.6 mmol/l. |