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Serum/plasma potassium ion concentration (measured by ion-selective electrode)

Published: August 9, 2026Updated: August 17, 2026

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

Quick summary

["Potassium levels can affect heart health and muscle function—keep them balanced for normal body function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
72950-9
Short code
Spironolactone (neut) IgG SerPl Ql FC
Synonyms
Spironolactone (neut) IgG SerPl Ql FC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
60
Ref high
170
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
83540
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 certain medications that affect potassium levels. It can also help monitor long-term health, especially if you have heart issues or take diuretics.

What to Expect Before the Test

No special preparation is needed unless your doctor instructs otherwise. You may be asked to fast for 8–12 hours before the test if it involves a blood draw, but potassium tests are usually done on any blood sample.

What Happens During the Test?

A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The test is quick and takes only a few minutes.

What Do the Results Mean?

Results are compared to a standard range, but exact values can vary by lab. Low potassium may cause muscle weakness or irregular heartbeat, while high levels can lead to heart rhythm problems or nausea. Your doctor will discuss your specific results with you.

Reference range

NCBI: Serum Iron Male 65-180; Female 50-170 µg/dLN/A

Specimen: serum

Fasting for 12 hours preferred. Iron supplements should be stopped 24 hours before if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Potassium level (serum/plasma)

Frequently asked questions

What causes potassium levels to be too high or too low?
Potassium imbalances can result from kidney problems, heart conditions, certain medications (like diuretics or potassium-sparing drugs), excessive sweating, or conditions like diabetes or vomiting. High potassium is especially dangerous for people with heart disease, while low potassium can weaken muscles or disrupt heart rhythms.
How often should I get this test?
Your doctor will determine how often you need this test based on your health, symptoms, or ongoing treatments. Regular monitoring may be needed if you have chronic conditions like kidney disease or heart problems.
Can I eat or drink before this test?
Most potassium tests don’t require fasting, but if your blood sample is for other tests, follow your doctor’s instructions. Avoid excessive salt intake 24 hours before if noted by your provider.
  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 17, 2026. · Read our editorial policy