The normal value for serum potassium is between 3.7 to 5.2 milliequivalent per liter. Serum potassium that measures over 5.2 milliequivalent per liter is considered high, as recorded by the U.S. National Library of Medicine.
The term for high potassium is hyperkalemia. Hyperkalemia may cause nausea or a slow, irregular pulse, according to the U.S. National Library of Medicine. High potassium levels in the blood may point to other conditions such as Addison's disease, kidney failure or tumors, or they may be a side effect of certain drugs such as chemotherapy or dietary supplements. Treatments focus on the underlying cause of hyperkalemia. For example, if the hyperkalemia is the result of kidney failure, the patient may require kidney dialysis.