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Creatinine Clearance (from 24-hour urine collection)

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

This test measures how well your kidneys filter waste products, including creatinine, over a full day. It helps assess kidney function and blood flow to the kidneys.

Quick summary

["Kidney function check using urine and blood creatinine levels over 24 hours."]

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

Key facts at a glance

LOINC
42288-1
Short code
Deprecated CT Abd Bx needle guide
Synonyms
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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 you have symptoms like fatigue, swelling, or frequent urination, or if you’re at risk for kidney problems (e.g., diabetes, high blood pressure). It’s also used to monitor kidney function before surgeries or treatments.

How the Test Works

You’ll collect all your urine over 24 hours in a special container. Blood is drawn at the start and end to measure creatinine levels. The test calculates how much creatinine your kidneys filter daily.

Sample Collection Process

You’ll receive clear instructions to collect every drop of urine for 24 hours, including at night. Store the urine in a cool place. Blood samples are taken on the first and last day of collection.

What to Expect Before the Test

No special preparation is needed, but drink plenty of water to support kidney function. Avoid certain medications (like NSAIDs) that may affect kidney health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low creatinine clearance may indicate kidney damage or disease, while high levels could suggest dehydration or kidney issues. It’s critical for diagnosing and managing chronic kidney disease, kidney stones, or other conditions affecting kidney function.

Short name

24-Hour Urine Creatinine Clearance

Frequently asked questions

How long does the urine collection last?
The urine collection period lasts exactly 24 hours, from midnight to midnight. You’ll need to collect every drop of urine in a special container.
What if I miss a urine sample?
If you miss any urine sample, you’ll need to restart the collection process. Missing even a small amount can affect the accuracy of the test results.
Can I eat or drink normally during the test?
Yes, you can eat and drink normally, but drink extra water to help your kidneys work properly. Avoid alcohol or large amounts of caffeine, as they may impact kidney function temporarily.
  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