Potassium Blood Test
A potassium blood test measures the level of this essential electrolyte to ensure proper heart, muscle, and nerve function.
What is a potassium blood test?
Potassium is an electrolyte—an electrically charged mineral—that helps control fluid balance, acid-base balance, and muscle and nerve activity. While most potassium is stored inside your cells, a small amount circulates in your blood. Your kidneys regulate these levels by removing excess potassium through urine.
Why do I need a potassium blood test?
This test is often part of an electrolyte panel used to monitor conditions like kidney disease, high blood pressure, diabetes, or adrenal gland disorders. It is also used if you take medications that affect potassium levels.
Symptoms of high potassium (hyperkalemia) include:
- Arrhythmia (irregular heartbeat).
- Fatigue and muscle weakness.
- Nausea, numbness, or tingling.
Symptoms of low potassium (hypokalemia) include:
- Irregular heartbeat.
- Muscle cramps, twitching, or weakness.
- Fatigue, nausea, and constipation.
What do the results mean?
High potassium (hyperkalemia) may be caused by kidney disease, Addison disease, injuries or burns, poorly controlled Type 1 diabetes, certain medications (diuretics or antibiotics), or excessive intake of potassium supplements.
Low potassium (hypokalemia) may be caused by prescription diuretics, fluid loss (diarrhea, vomiting, or sweating), laxative overuse, adrenal gland disorders (Cushing's syndrome or aldosteronism), kidney disease, or alcohol use disorder.
Note: Avoid natural black licorice for two weeks before the test, as it may lower potassium levels. Additionally, avoid clenching your fist during the blood draw, as this can cause a temporary, inaccurate spike in results.