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24-Hour Urinary Potassium Excretion

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

This test measures how much potassium your body excretes in urine over a 24-hour period. It helps assess kidney function and electrolyte balance.

Quick summary

["Understanding your potassium loss helps diagnose kidney issues or electrolyte imbalances."]

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

Key facts at a glance

LOINC
9078-7
Short code
Potassium intake 12h
Synonyms
Potassium intake 12h
Category
electrolyte
Sample
serum
Container
Red-top tube (SST)
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
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 This Test Matters

Your kidneys play a key role in balancing potassium, a mineral essential for nerve and muscle function. This test checks if your kidneys are removing enough potassium through urine, which can be affected by conditions like kidney disease, certain medications, or hormonal imbalances.

What to Expect Before the Test

You’ll typically collect all urine for 24 hours, starting after midnight on one day and ending after midnight the next. Drink plenty of fluids to ensure adequate urine production. Avoid certain medications (like potassium-sparing diuretics) unless approved by your provider.

How the Test Works

The collected urine is analyzed to determine the total potassium content excreted. This provides insight into kidney function and how well your body is managing potassium levels.

Common Reasons for Testing

Doctors may order this test if you have symptoms like muscle weakness, cramps, or irregular heartbeat, or if you have conditions like kidney disease, diabetes, or certain medications that affect potassium levels.

Reference range

Adult: 3.5-5.0 mmol/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24h Urine Potassium

Frequently asked questions

What Does a High or Low Result Mean?
High potassium levels (hyperkalemia) may indicate kidney problems, excessive potassium intake, or certain medications. Low potassium levels (hypokalemia) could signal kidney dysfunction, vomiting, diarrhea, or excessive sweating. Your provider will interpret results in the context of your overall health.
How Often Should I Get This Test?
Your provider will determine the frequency based on your health status, symptoms, and treatment plan. Regular monitoring may be needed if you have chronic kidney disease or take medications that affect potassium.
Can I Eat or Drink Normally Before the Test?
Yes, you can eat and drink as usual unless your provider specifies otherwise. Avoid high-potassium foods (like bananas, spinach, or nuts) if instructed, as they may affect results.
  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