Normal and Abnormal Potassium Blood Test Results

Potassium is a mineral that is essential to our bodies. For example, it is critical to the following processes:

• Regulation of water balance and pH balance in blood and tissues
• Energy metabolism
• Protein synthesis
• Carbohydrate metabolism
• Glycogen and glucose metabolism (i.e., the conversion of glucose into glycogen for future energy storage)
• Growth and maintenance of muscle tissue
• Conduction of nerve impulses
• Regulation of heartbeat

A potassium test simply measures the amount of potassium that is in the blood. A normal potassium level blood test result is 3.6 to 4.8 milliequivalents of potassium per each liter of blood. Those who have less than 3.6 milliequivalents of potassium per each liter of blood are said to have hypokalemia, and those who have greater than 4.8 milliequivalents of potassium per each liter of blood are said to have hyperkalemia. In particular, a blood potassium level that is equal to or less than 2.5 milliequivalents per liter, or is greater than 6.0 milliequivalents per liter, is a sign of a very dangerous underlying condition and requires immediate medical attention.

A person who is hypokalemic (low potassium level) may experience one or more of the following symptoms: fatigue, constipation, muscle cramps, and arrhythmias (abnormal heartbeat). Hypokalemia usually is the result of an abnormally high loss of potassium from the digestive tract or urine. The most common causes of this excess loss of potassium are:

• Diarrhea
• Excessive vomiting
• Laxative overuse
• Ingestion of water pills
• Chronic kidney failure
• Overproduction of the hormone aldosterone, which regulates blood potassium levels, by the adrenal glands

The typical treatment course for hypokalemia is to take potassium supplements. (If you believe that you may be hypokalemic, please consult your doctor before taking any such supplements. Overuse of potassium supplements can be hazardous to your health, as described in the next section.)

A person who is hyperkalemic (high potassium level) may experience one or more of the following symptoms: nausea, muscle weakness, tingling sensations, fatigue, slowed heartbeat, weak pulse, and, in the worst cases, cardiac arrest. Very commonly, excess blood potassium is due to either acute (sudden) kidney failure or chronic (gradual) kidney failure, as one of the main functions of the kidneys is to excrete excess potassium into the urine for discharge from the body.

Less common causes of hyperkalemia include:

• Muscle fiber breakdown, which in turn releases potassium into the blood (this breakdown often is seen in alcoholics and drug abusers)
• Insufficient levels of aldosterone (a condition known as Addison's disease)
• Certain blood vessel relaxing drugs
• Type 1 diabetes
• Overuse of potassium supplements
• Red blood cell loss, typically due to burn or other injury

If you suspect that you may have hyperkalemia, the best course is to contact your doctor right away. Hyperkalemia is a serious condition that requires immediate medical attention. Your doctor will determine the exact cause of the excess potassium in your blood and then will recommend a treatment plan based on knowledge of that cause. (For example, if you are experiencing kidney failure, your doctor likely will recommend kidney dialysis treatment.)

Mayo Clinic, Hyperkalemia (high potassium): http://www.mayoclinic.com/health/hyperkalemia/MY00940

Mayo Clinic, Low potassium (hypokalemia): http://www.mayoclinic.com/health/low-potassium/MY00760

Medline Plus, National Institutes of Health, Potassium test: http://www.nlm.nih.gov/medlineplus/ency/article/003484.htm