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Creatinine, 24-Hour Urine

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

Measures the total creatinine released in urine over 24 hours. It helps assess kidney function and can help determine whether a urine collection was complete.

Quick summary

["This test measures how much creatinine your kidneys excrete in a full day's urine."]

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

Key facts at a glance

LOINC
13821-4
Short code
UUN/Creat 24h Ur
Synonyms
UUN/Creat 24h Ur
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

Creatinine is a waste product formed by muscles and filtered by the kidneys. This test measures the total amount of creatinine collected in urine over 24 hours.

Why might I need this test?

A 24-hour urine creatinine measurement may be used to assess kidney function, determine the amount of certain substances excreted by the body, or check the completeness of another 24-hour urine collection.

How is the test performed?

You collect all urine for a full 24-hour period in a special container provided by your healthcare provider. The laboratory then measures the creatinine in the collected sample.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory, including the exact start and end times. If a sample is missed, ask how to proceed, and store or refrigerate the container as instructed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A higher amount of urinary creatinine can occur with increased muscle mass, intense exercise, certain medicines, or some kidney conditions. A lower amount may occur with reduced kidney function, low muscle mass, poor intake, or an incomplete collection, so results are interpreted alongside other tests and clinical information.

Short name

24-Hour Urine Creatinine

Frequently asked questions

Do I need to collect every drop of urine?
Usually, all urine produced during the 24-hour period should be collected. Follow the container and timing instructions carefully, and ask the laboratory what to do if a sample is accidentally missed.
Why is the urine kept for 24 hours?
Measuring one day's total excretion provides a more representative result than a single urine sample. It also helps show whether the collection was complete.
Does an abnormal result mean I have kidney disease?
Not by itself. Urine creatinine is interpreted with other kidney tests, medications, muscle mass, activity, and the completeness of the collection.
  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