What High Levels of Potassium Mean

Q. My blood test showed high levels of potassium. What does this mean?

A. Potassium, a mineral we get from food, is important for cell function. Potassium helps regulate your heart rate, muscles, nerves, and fluids. As crucial as it is, however, you can have too much of it.

It’s your kidney’s function to flush out excess potassium. A normal blood potassium level ranges from 3.5 to 5.0 mEq/l (milliequivalent per liter). A high potassium level can indicate your kidneys aren’t functioning correctly.

Impaired kidney function can arise from a variety of conditions, among them Addison’s disease, in which the adrenal glands are damaged; adverse effects of certain medications; damage from illicit drugs or excessive alcohol; tumors; or the ingestion of salt substitutes.

If your potassium level were to exceed 6.0 per liter—a condition called hyperkalemia—you’d need immediate attention to avoid potentially serious and even fatal complications, such as heart-rate irregularities and paralysis.

If your potassium level is borderline high, your doctor may simply advise you to make certain dietary changes, such as avoiding foods rich in potassium—bananas and potatoes, for example—until your potassium level drops.

Interestingly, potassium levels can occasionally be falsely elevated during the blood draw as a result of poor phlebotomy technique, prolonged application of the tourniquet, a clenched fist, or an incorrect needle size.

Any of these events during the phlebotomy procedure, in addition to mishandling the tube of blood afterward, can cause excessive potassium to leak from cells in the blood specimen and raise potassium values.

Read more about how a potassium imbalance can affect your health.

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HealthAfter50 was published by the University of California, Berkeley, School of Public Health, providing up-to-date, evidence-based research and expert advice on the prevention, diagnosis, and treatment of a wide range of health conditions affecting adults in middle age and beyond. It was previously part of Remedy Health Media's network of digital and print publications, which also include HealthCentral; HIV/AIDS resources The Body and The Body Pro; the UC Berkeley Wellness Letter; and the Berkeley Wellness website. All content from HA50 merged into Healthcentral.com in 2018.