Kidney system

Potassium

K

A critical intracellular electrolyte essential to heart and muscle function.

What is it

Potassium — in plain English.

Potassium is the primary intracellular electrolyte and is essential to heart rhythm, muscle function, and nerve signaling. Levels are tightly regulated.

Why it's measured

What K can reveal.

Potassium imbalance has clinical significance in cardiac and neuromuscular function in published research.

Reference range

Where most laboratories draw the standard line.

Standard laboratory reference

3.5 – 5.0 mEq/L

Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.

What results may indicate

Higher vs. lower K — at a high level.

Elevated

Has been associated with kidney dysfunction and certain medications in research literature; can affect heart rhythm.

Lower

Has been associated with diuretic use and GI losses in research literature; can affect heart rhythm.

These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.

When it's measured

When K is typically run.

Part of standard electrolyte panels.

Related markers

Often measured alongside K.

Common questions

Questions people ask about Potassium

What is Potassium?

Potassium is the primary intracellular electrolyte and is essential to heart rhythm, muscle function, and nerve signaling. Levels are tightly regulated.

Why is Potassium measured?

It's one of the markers used to build a fuller picture of your health. On its own it tells you very little, so it's most informative when reviewed alongside related markers.

How is Potassium tested?

It's measured from a standard blood draw at Quest or LabCorp. Potassium is one of the markers included in the OPTML Apex Panel, where your results are read across systems and reviewed by a U.S.-licensed physician.

What should I do with my Potassium result?

Reference ranges vary by laboratory, and a single value rarely tells the whole story. Review your result with a physician in the context of your other markers, symptoms, and history.

Not sure which panel is right for you?

Potassium is one signal among many. Answer a few quick questions and we’ll point you to the panel that fits.

Measured in

K is one of 160 biomarkers in the Apex Panel.

A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.

Explore the Apex Panel
160 biomarkers13 body systemsPhysician-reviewed
Back to all biomarkers

This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.