Skip to content

Creatinine Clearance (24-hour urine collection)

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

This test measures how well your kidneys filter waste products, specifically creatinine, over a full day using your urine.

Quick summary

["Assesses kidney function by tracking how efficiently your kidneys remove waste from your blood."]

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

Key facts at a glance

LOINC
46368-7
Short code
Deprecated CT Brst Bx needle guide
Synonyms
Deprecated CT Brst Bx needle guide
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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 disease, monitor kidney function over time, or evaluate how well a kidney transplant or other kidney treatments are working. It’s also used to check for conditions like chronic kidney disease or to guide treatment plans for conditions affecting kidney function.

How the Test Works

You’ll collect all your urine for a full 24-hour period in a special container. The test measures the amount of creatinine in your urine and compares it to a blood sample taken at the start of the collection period. Creatinine is a waste product naturally produced by your muscles and filtered by your kidneys.

Sample Collection Process

To prepare, empty your bladder before starting the collection. Use the container provided to catch all urine for the entire day, including at night. Replace the lid tightly after each void. Bring the full container to your lab with a record of the total urine volume collected.

What to Expect After the Test

After collection, the lab processes your urine sample to determine creatinine levels. You’ll receive results from your doctor, who will interpret them in relation to your overall health and any symptoms you may have.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Creatinine Clearance

Frequently asked questions

How does creatinine clearance differ from a simple blood creatinine test?
Creatinine clearance is a more comprehensive measure of kidney function because it accounts for the entire volume of urine produced over 24 hours. While a blood creatinine test shows how much creatinine is in your blood, clearance reflects how well your kidneys are filtering waste from your bloodstream over time. This test is particularly useful for detecting early kidney problems or monitoring kidney disease progression.
What does a low creatinine clearance indicate?
A low creatinine clearance suggests impaired kidney function, meaning your kidneys are not filtering waste products efficiently. This could indicate chronic kidney disease, dehydration, or other conditions affecting kidney health. Your doctor will discuss further steps, such as lifestyle changes or additional tests, based on the results.
Can diet affect creatinine clearance results?
Yes, diet can influence creatinine levels. High-protein foods or muscle mass can increase creatinine production, potentially affecting the test results. To minimize variability, your doctor may advise avoiding extreme dietary changes before testing or may recommend a standard diet for the 24-hour period.
  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