Potassium (Serum) Concentration
This test measures the amount of potassium, a mineral essential for heart function and muscle contractions, in your blood serum.
["Potassium levels help assess heart health and electrolyte balance."]
Key facts at a glance
- LOINC
- 82722-0
- Short code
- Potassium RBC-mCnc
- Synonyms
- Potassium RBC-mCnc
- Category
- electrolyte
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 3.5
- Ref high
- 5
- Critical range
- 2.5 N/A – 6.5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84132
- SNOMED
- 110742001
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test to check for conditions affecting your heart, kidneys, or electrolyte balance. It can also help diagnose or monitor symptoms like muscle weakness, irregular heartbeat, or signs of dehydration or kidney problems.
When Might You Need This Test?
You might need this test if you have symptoms like unusual fatigue, muscle cramps, irregular heartbeat, or if you’re being treated for conditions like heart disease, kidney disease, or certain medications that affect potassium levels.
What Does the Test Involve?
A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab where potassium levels are measured using a specialized method to determine your serum potassium concentration.
What Are Common Causes of Abnormal Results?
Low potassium (hypokalemia) can occur due to conditions like vomiting, diarrhea, excessive sweating, or certain medications. High potassium (hyperkalemia) may result from kidney problems, severe dehydration, or certain medical conditions or treatments.
Reference range
Adult: 3.5-5.0 mmol/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Potassium plays a critical role in maintaining proper heart rhythm, muscle function, and nerve signaling. Abnormal levels can lead to serious health issues, such as irregular heartbeats, muscle weakness, or even life-threatening conditions. Your provider will interpret results in the context of your overall health and symptoms.
Short name
Serum Potassium
Frequently asked questions
What does a low potassium level mean?
What does a high potassium level mean?
How often should I get this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy