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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 from your blood by tracking creatinine levels in your urine over 24 hours.

Quick summary

["Assesses kidney function by evaluating urine flow and waste removal efficiency."]

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

Key facts at a glance

LOINC
42267-5
Short code
Deprecated CT LN 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 to check if your kidneys are working properly, especially if you have symptoms like swelling, fatigue, or changes in urine output. It helps diagnose or monitor kidney disease, high blood pressure, or diabetes.

How the Test Works

You’ll collect all urine for a full 24-hour period in a special container. Blood is drawn once to measure baseline creatinine levels. The test compares how much creatinine appears in your urine versus your blood to estimate kidney function.

What to Expect Before the Test

No special preparation is needed, but drink plenty of water to help your kidneys produce urine. Avoid certain medications (like NSAIDs) that may affect kidney function unless approved by your doctor.

What to Expect During the Test

You’ll collect urine samples every few hours for 24 hours. A simple blood draw is done once to measure baseline creatinine. The test is painless but requires consistency in urine collection.

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 long does the 24-hour urine collection take?
The urine collection itself takes about 24 hours, but you’ll need to carefully track and store each sample to ensure accuracy. Your healthcare provider will guide you through the process.
Can I eat or drink normally during the test?
Yes, but drink plenty of fluids to help your kidneys produce urine. Avoid excessive caffeine or alcohol, as they can affect urine volume and clarity. Follow your doctor’s specific instructions.
Will I need to take any special medications before or after the test?
Some medications, like NSAIDs (e.g., ibuprofen), may impact kidney function. Always check with your doctor before stopping or changing any medications. They may also prescribe temporary adjustments if needed.
  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