Potassium (Serum) Concentration
This test measures the amount of potassium, a mineral essential for heart function and nerve signaling, in your blood serum.
["Potassium levels help assess heart health and electrolyte balance."]
Key facts at a glance
- LOINC
- 32550-6
- Short code
- Potassium ?Tm sub Ur Qn
- Synonyms
- Potassium ?Tm sub Ur Qn
- Category
- electrolyte
- Sample
- urine
- Container
- Sterile urine container
- 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
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- 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 like low or high potassium levels, which can affect your heart rhythm, muscle function, or kidney health. It’s often done when you have symptoms such as muscle weakness, irregular heartbeat, or signs of dehydration or kidney problems.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it’s part of a broader blood panel. Bring any medications you’re currently taking, as they can influence results.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. The blood sample is then sent to a lab for analysis. The test typically takes a few minutes, and you may feel slight discomfort or bruising at the injection site.
What the Results Mean
Results are compared to standard reference ranges to determine if your potassium levels are within normal limits. Abnormal results may signal conditions like kidney disease, heart problems, or certain medications affecting electrolyte balance.
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.
◆Associated findings1
Short name
Serum Potassium
Frequently asked questions
Potassium is critical for maintaining proper heart rhythm, muscle function, and nerve signaling. Low potassium (hypokalemia) can cause muscle weakness, irregular heartbeat, or fatigue, while high potassium (hyperkalemia) may lead to heart complications like arrhythmias or muscle cramps.
Low potassium can result from conditions like kidney problems, excessive vomiting or diarrhea, certain medications (e.g., diuretics), or poor dietary intake of potassium-rich foods. It may also occur due to metabolic issues or hormonal imbalances.
High potassium levels can be caused by kidney failure, severe dehydration, certain medications (e.g., potassium-sparing diuretics), or conditions like Addison’s disease. Excessive intake of potassium supplements or salt substitutes can also contribute.
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