Interpret Your Potassium Results
Enter your K value below and get an instant, free AI interpretation — a plain-English explanation checked against WHO/IFCC reference ranges.
Medical Disclaimer
This AI-generated interpretation is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results may vary based on individual health factors not captured here.
Always consult a qualified healthcare professional before making any health decisions. Read full disclaimer →
Potassium Normal Ranges
Potassium is the primary intracellular cation and is essential for maintaining the resting membrane potential of cells, particularly in cardiac muscle and nerves.
| Reference Range | Unit | Notes |
|---|---|---|
| 3.5 – 5 | mEq/L | — |
Also reported in: mmol/L.
Critical (Panic) Values
Critical Low: < 2.5 mEq/L. Critical High: > 6.5 mEq/L. Values outside these limits require immediate clinical attention.
Why Doctors Order the Potassium Test
Potassium disorders are among the most dangerous electrolyte emergencies. Both hypokalemia and hyperkalemia can cause fatal cardiac arrhythmias — hyperkalemia causes peaked T waves, widened QRS, and ventricular fibrillation; hypokalemia causes U waves, prolonged QT, and torsades de pointes.
How to Enter Your K Result
Potassium can be reported in mEq/L or mmol/L. Choose the unit printed next to your result on the lab report so it is compared with the matching reference range.
What a Low or High K Can Be Associated With
Below the reference range
- Diuretics (thiazides, loop diuretics — most common cause)
- Vomiting and nasogastric suction
- Diarrhea and laxative abuse
- Hyperaldosteronism (primary or secondary)
- Hypomagnesemia (potassium wasting accompanies magnesium deficiency)
Above the reference range
- Kidney failure (most common — reduced excretion)
- ACE inhibitors and ARBs (reduce aldosterone effect)
- Potassium-sparing diuretics (spironolactone, amiloride)
- Addison's disease (adrenal insufficiency)
- Metabolic acidosis (potassium shifts out of cells)
This interpreter flags a result at or below 2.5 mEq/L or at or above 6.5 mEq/L as a critical value. Results that extreme are uncommon — contact your doctor promptly, and seek urgent medical care if you feel unwell.
These are common associations, not a diagnosis. A single result is read alongside your symptoms, history and other tests — discuss it with your doctor.
What Can Change Your K Result
Before you read too much into a result, consider whether any of these applied:
- Hemolysis (most common cause of falsely high potassium — red cells contain 20–50× more potassium than plasma)
- Prolonged tourniquet with fist clenching (localizes potassium from muscle, raises local potassium)
- Cold temperature (potassium leaks from cells in cold storage)
- Thrombocytosis or leukocytosis (platelets and white cells release potassium on clotting)
Preparing for the test: No special preparation. Potassium can be falsely elevated by hemolysis (most common lab artifact) — the specimen should be processed promptly without excessive shaking or delay.
Symptoms That Often Prompt K Testing
- Muscle weakness and cramps (hypokalemia)
- Palpitations and irregular heartbeat
- Constipation
- Tingling and numbness
- Muscle paralysis (severe hypokalemia)
Want the full clinical guide to Potassium?
Reference ranges, causes, symptoms, preparation, and FAQs.