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Creatinine, 24-Hour Urine

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

A 24-hour urine test measures creatinine excretion and can help assess kidney function when interpreted with other laboratory results.

Quick summary

["This test measures how much creatinine is released in the urine over 24 hours."]

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

Key facts at a glance

LOINC
44352-3
Short code
PETN/Creat 24h Ur
Synonyms
PETN/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 produced by the muscles and filtered by the kidneys. This test measures the amount of creatinine excreted in urine collected over a 24-hour period.

Why might I need this test?

A clinician may use this test to assess kidney function or to help interpret other urine measurements. When combined with blood creatinine, urine volume, and related tests, it can also help evaluate how effectively the kidneys filter waste.

How is the test performed?

You collect all urine for a full 24 hours, beginning and ending at the times specified by the laboratory. The laboratory measures the creatinine in the collected sample and may also report the total 24-hour urine volume.

How do I prepare for the test?

Follow the laboratory's collection instructions exactly, including the start and end times and any refrigeration requirements. Record or note any missed urine collection, and do not change medications unless your clinician instructs you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Unexpected creatinine excretion can reflect differences in muscle mass, recent exercise, hydration, kidney function, medications, or incomplete urine collection. The result is most informative when interpreted with serum creatinine, estimated filtration rate, urine volume, and other kidney tests. No single urine creatinine result by itself establishes a diagnosis.

Short name

24-hour urine creatinine

Frequently asked questions

What does a 24-hour urine creatinine test measure?
It measures the total amount of creatinine excreted in the urine collected over 24 hours. Creatinine is a muscle waste product that is primarily cleared by the kidneys.
How is the 24-hour urine sample collected?
Collect urine into the provided container every time during the specified 24-hour period. Follow the laboratory's instructions for storage, the start and end times, and documenting any missed collection.
What can cause an unexpected result?
Results may be affected by muscle mass, recent exercise, hydration, medications, kidney disease, and collection completeness. Your clinician will interpret the result alongside your other laboratory tests and medical history.
  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