POTASSIUM - serum

Application: Monitoring potassium status in patients on diuretics or on intravenous therapy, and in those with renal disease, acid-base disturbances or GI fluid losses.

Explanation:  Potassium (K+) is the major intracellular cation. It is excreted (but not reabsorbed) by the kidney; inadequate K+ in the diet (or by IV if unable to eat) will result in rapidly falling serum K+ levels.  Decreased levels are also found in association with diuretic therapy, vomiting or diarrhea, alkalosis, and with aldosterone excess (as sodium is retained, K+ is lost).

Increased K+ levels are usually found in acidosis, tissue damage, renal failure and aldosterone deficiency. This electrolyte has profound effects on heart rate and contractility.

 Specimen: 5 ml blood in red- or green-top tube.


Reference Potassium Interval:
            3.5-5 mEq/L      (Adult)
            3.4-4.7 mEq/L   (Child)
            4.1-5.3 mEq/L   (Infant)
            3.9-5.9 mEq/L   (Newborn)