Potassium concentration in whole blood
This test measures the amount of potassium, a vital mineral electrolyte, in your blood. Potassium helps regulate heart rhythm, muscle function, and fluid balance.
["Potassium levels help assess heart health and electrolyte balance."]
Key facts at a glance
- LOINC
- 39789-3
- Short code
- Potassium BldV-sCnc
- Synonyms
- Potassium BldV-sCnc
- 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 doctor may order this test to check for conditions affecting potassium levels, such as kidney problems, heart issues, or certain medications that alter electrolyte balance. It can also help diagnose symptoms like muscle weakness, irregular heartbeat, or nausea.
What to Expect Before the Test
No special preparation is usually needed. If you’re having blood drawn, you may feel a slight pinch, but it’s generally quick and painless. Avoid eating or drinking for 8–12 hours before if your test is done on an empty stomach (e.g., for certain electrolyte panels).
What Happens During the Test?
A healthcare provider will insert a small needle into a vein in your arm to draw blood. The sample is then sent to a lab for analysis. The test typically takes a few minutes, and you may experience mild bruising or soreness afterward.
What the Results Mean
Results are compared to standard ranges for your age and health. Low potassium (hypokalemia) or high potassium (hyperkalemia) can signal underlying health concerns, but interpretation depends on your overall medical picture.
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 is critical for nerve and muscle function, including your heart’s ability to beat regularly. Abnormal levels can cause serious complications, such as arrhythmias, muscle cramps, or even heart failure. Your doctor will review results alongside other symptoms and tests to determine next steps.
Short name
Potassium (K+)
Frequently asked questions
How long does it take to get my potassium test results?
Can I eat or drink before this test?
What symptoms might indicate low or high potassium?
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