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Serum/plasma concentration of potassium (K+)

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

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

Quick summary

["Potassium levels help doctors check for heart issues, kidney problems, or other health concerns."]

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

Key facts at a glance

LOINC
7349-4
Short code
Grape Raisin BasoBnd Ab Qn
Synonyms
Grape Raisin BasoBnd Ab Qn
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
lhr
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 if you have symptoms like muscle weakness, cramps, irregular heartbeat, or signs of kidney problems. It can also be part of routine check-ups or before certain treatments.

What to Expect Before the Test

No special preparation is needed, but avoid eating or drinking for at least 8 hours before the blood draw if instructed. Stay hydrated unless your doctor advises otherwise.

How the Test Works

A small amount of blood is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to measure potassium levels.

What the Results Mean

Results are compared to standard ranges to identify if your potassium level is too high (hyperkalemia) or too low (hypokalemia). Your doctor will discuss these findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Potassium levels are crucial for normal heart function, nerve signaling, and muscle contractions. Abnormal levels can cause serious health problems, including heart rhythm disturbances or muscle weakness.

Short name

Potassium level

Frequently asked questions

What causes potassium levels to be too high?
High potassium levels (hyperkalemia) can result from kidney problems, certain medications, or conditions like adrenal insufficiency. Severe cases may require medical treatment.
What causes potassium levels to be too low?
Low potassium levels (hypokalemia) can occur due to vomiting, diarrhea, excessive sweating, certain medications, or poor kidney function. It may also be linked to conditions like diabetes or eating disorders.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status, symptoms, and other medical conditions. Regular monitoring may be recommended if you have chronic health issues.
  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