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Saturday, July 18, 2015

Potassium, the Major Intracellular Cation




Potassium is the primary intracellular cation. It is also an integral part of the transmission of nerve impulses.  It participates in the sodium-potassium pump in the body. 

Unhemolyzed serum should be used because hemolysis will markedly increase the potassium values because potassium is present in large amounts inside the cell.





Clinical Significance

1.      Hyperkalemia – increased concentration of potassium in the bloodstream. It’s found in the following conditions:

         Decreased renal excretion

         Acute or chronic renal failure
         Hypoaldosteronism
         Addison’s disease
         Diuretic

·         Cellular shift

         Acidosis
         Muscle/cellular injury
         Chemotherapy
         Leukemia
         Hemolysis

Increased intake

             Oral or IV potassium replacement therapy

-          Artifactual

                        Sample hemolysis
                        Thrombocytosis
                        Prolonged tourniquet use of excessive fist clenching

2.      Hypokalemia – decreased concentration of potassium in the blood stream, seen in the following conditions:

            GI loss

                        - Vomiting
                        - Diarrhea
                        - Gastric suction
                        - Intestinal tumor
                        - Malabsorption
                        - Cancer therapy
                        - Large doses of laxatives

          Normal values:

                           K = 3.5-5.3

         Plasma and serum: 3.4 – 5.0 mmol/L
         Urine: 25 -125 mmol/L



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