Skip to content

Serum or plasma potassium concentration (mass concentration)

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

This test measures the amount of potassium, a mineral essential for heart function and nerve signaling, in your blood.

Quick summary

["Potassium helps regulate heart rhythm and muscle contractions; low or high levels can cause serious health risks."]

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

Key facts at a glance

LOINC
30722-3
Short code
XR port Skull 1V
Synonyms
XR port Skull 1V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-portable
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 potassium testing if you have symptoms like muscle weakness, cramps, irregular heartbeat, or signs of dehydration. It’s also checked during kidney function evaluations, before certain medications, or if you have conditions like heart disease or diabetes.

What to Expect During the Test

A blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it’s quick. No special preparation is needed unless instructed otherwise.

Factors That Can Affect Results

Certain foods (like bananas or spinach), medications (e.g., diuretics), or health conditions (like kidney disease) can influence potassium levels. Always tell your doctor about all medications or supplements you take.

Common Causes of Abnormal Results

Low potassium (hypokalemia) may occur from vomiting, diarrhea, or excessive sweating. High potassium (hyperkalemia) can result from kidney problems, certain medications, or severe dehydration.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Potassium Level

Frequently asked questions

What does a low potassium level mean?
A low potassium level may indicate conditions like vomiting, diarrhea, excessive sweating, or certain medications. It can also signal underlying health issues like kidney problems or hormonal imbalances. Your doctor will review your symptoms and other test results to determine the cause.
What does a high potassium level mean?
High potassium levels often point to kidney issues, severe dehydration, or certain medications. It can also be linked to conditions like heart disease or adrenal problems. Your doctor will assess your medical history and other tests to identify the reason.
How often should I get this test?
The frequency depends on your health status. People with chronic conditions like kidney disease or heart problems may need potassium tests more often. Your doctor will guide you on how often to check your levels based on your individual needs.
  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