Potassium

What is Potassium?

Potassium is the primary intracellular electrolyte, critical for maintaining cell membrane potential, nerve impulse transmission, and muscle contraction — especially cardiac muscle. Only 2% of total body potassium is in the blood; 98% is inside cells. Small changes in serum potassium can have life-threatening cardiac effects.

What might a high or low Potassium mean?

Both low potassium (hypokalemia) and high potassium (hyperkalemia) can cause dangerous heart-rhythm disturbances. Low potassium is associated with muscle weakness, cramps, and ECG changes; high potassium with characteristic ECG changes and, when severe, cardiac arrest. Potassium is one of the most consequential electrolytes when imbalanced.

What is the typical reference range for Potassium?

The general-population reference range shown here is 3.5 – 5.1 mmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Potassium?

It may be higher with: Kidney disease (reduced excretion), ACE inhibitors and ARBs, Potassium-sparing diuretics (spironolactone), Acidosis (shifts K out of cells), Tissue destruction (rhabdomyolysis, burns, tumor lysis), Adrenal insufficiency, Hemolyzed blood sample (common artifact!). It may be lower with: Diuretics (furosemide, hydrochlorothiazide), Vomiting and diarrhea, Excessive sweating, Insulin (shifts K into cells), Beta-agonists (albuterol), Magnesium deficiency (causes renal K wasting), Alkalosis, Poor dietary intake.