Potassium (Serum or Plasma) Concentration
This test measures the amount of potassium, a mineral essential for heart function and nerve signaling, in your blood.
["Potassium levels help assess heart health and electrolyte balance."]
Key facts at a glance
- LOINC
- 108797-2
- Short code
- Potassium Msmt SerPl
- Synonyms
- Potassium Msmt SerPl
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test to check for conditions like low potassium (hypokalemia), high potassium (hyperkalemia), kidney problems, or to monitor treatment effects, such as for heart rhythm issues or certain medications.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves a fasting sample. Avoid eating or drinking anything except water. If you’re on potassium-sparing diuretics or supplements, let your doctor know.
What Happens During the Test?
A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it’s quick and painless. The blood sample is sent to a lab for analysis.
What Do Results Mean?
Results are compared to a reference range, but exact values can vary by lab. Low potassium may cause muscle weakness or irregular heartbeats, while high potassium can lead to heart rhythm disturbances or weakness. Your doctor will interpret results in the context of your overall health.
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.
Abnormal potassium levels can indicate serious health issues, such as kidney disease, heart problems, or certain medications (e.g., diuretics, heart medications). Chronic imbalances may require lifestyle changes, dietary adjustments, or medical treatment to restore balance and prevent complications like muscle cramps, fatigue, or cardiac arrest.
Short name
Serum Potassium
Frequently asked questions
How often is this test repeated?
What symptoms might trigger a potassium test?
Can diet affect potassium test results?
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