Potassium (K)

Your cells, nerves, heart, and muscles need potassium to work properly. You can usually get most of the potassium that you need from the foods that you eat. Almost all of your body's potassium is inside your cells, but a small amount is in your blood. Your kidneys remove potassium in your urine (pee) to help keep the right amount of potassium in your blood. Potassium levels that are too high or too low may be a sign of a medical condition and may cause serious health issues.

Too much potassium in the blood is called hyperkalemia, and too little potassium in the blood is called hypokalemia. Either can be caused by a number of different conditions or factors. For example, higher levels can be seen with adrenal gland problems, sudden kidney failure, or some cases of diabetic acidosis, while lower levels may occur with certain water pills (diuretics) or a kidney problem called renal tubular acidosis.

Levels below about 3.0 mmol/L can cause noticeable muscle weakness and cramping, and levels below 2.5 mmol/L can be dangerous. On the high side, levels above 6.0 mmol/L often cause symptoms and can be a medical emergency, especially when potassium rises quickly, because of the risk of dangerous heart rhythms. Very high levels above 10.0 mmol/L can be fatal.

If your test results are not in the normal range, it doesn't always mean that you have a medical condition that needs treatment. To learn what your results mean, talk with your provider.