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Serum/plasma potassium ion concentration (mass concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of potassium, a mineral electrolyte, in your blood. Potassium helps regulate heart rhythm, muscle function, and fluid balance.

Quick summary

["Potassium levels help assess heart health and electrolyte balance."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
13224-1
Short code
Deprecated C trach G+F+K Ab SerPl-aCnc
Synonyms
Deprecated C trach G+F+K Ab SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 low (hypokalemia) or high (hyperkalemia) potassium levels, which can cause symptoms like muscle weakness, irregular heartbeat, or fatigue. It’s often done when you have symptoms of electrolyte imbalance, kidney disease, or conditions affecting heart function.

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 drawing blood from a vein. If you’re on a potassium-restricted diet, follow your doctor’s instructions.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a small needle. The blood sample is sent to a lab for analysis using an automated method to measure potassium levels.

What the Results Mean

Results are compared to standard reference ranges, but exact values can vary by lab. Low potassium may indicate conditions like vomiting, diarrhea, or certain medications, while high potassium could signal kidney problems or severe dehydration.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum/plasma potassium

Frequently asked questions

Why might my potassium levels be checked?
Your doctor may monitor potassium levels if you have symptoms like muscle cramps, heart palpitations, or unexplained fatigue. It’s also used to diagnose or manage conditions like heart disease, kidney disorders, or metabolic imbalances.
How often should I get this test?
The frequency depends on your health status. Routine checks may occur if you have chronic conditions like diabetes, heart disease, or kidney problems. Your doctor will determine how often testing is needed based on your needs.
What can affect potassium levels?
Several factors can influence potassium levels, including diet (e.g., high-potassium foods like bananas), certain medications (e.g., diuretics), kidney function, and conditions like dehydration or severe vomiting.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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