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24-Hour Urinary Volume (Kidney Function)

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

This test measures how much urine you produce over a full day, helping doctors assess kidney function and fluid balance.

Quick summary

["Understanding your daily urine output can help identify kidney or fluid-related health concerns."]

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

Key facts at a glance

LOINC
15317-1
Short code
Volume Kidney-L by AUT
Synonyms
Volume Kidney-L by AUT
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-derived-aut
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 Is Done

Your doctor may order this test if they suspect kidney problems, dehydration, overhydration, or conditions affecting fluid balance, such as heart or liver disease. It can also help monitor treatments for conditions like diabetes or kidney stones.

What to Expect Before the Test

You’ll collect all urine for 24 hours, typically starting after midnight and ending the same day the next morning. Store the urine in a refrigerator or cool container, and keep a log of intake/output to ensure accuracy.

During the Test

No special preparation is needed beyond collecting urine in a container. Bring the sample to your lab with the 24-hour log to confirm completeness.

What the Results Mean

Results help determine if your kidneys are filtering fluids properly. Abnormally high or low volumes may signal underlying health issues requiring further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormally low urine output (oliguria) could indicate dehydration, kidney failure, or blockages, while excessively high output (polyuria) may signal diabetes, diabetes insipidus, or kidney disease. Your doctor will interpret results in context with your symptoms and medical history.

Short name

24-hour urine volume

Frequently asked questions

How is urine volume measured?
Urine volume is measured by the total amount collected in a 24-hour period, typically reported in milliliters (mL).
What causes unusually high or low urine output?
High urine output can be due to diabetes, kidney disease, or excessive fluid intake. Low urine output may result from dehydration, kidney problems, or heart/liver disease.
Do I need to fast before this test?
No fasting is required. Focus on collecting all urine for the full 24-hour period, including first-morning urine on the first day.
  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