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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, using a 24-hour urine sample. It helps assess kidney function and blood pressure management.

Quick summary

["A key measure of kidney health and blood pressure control over a full day’s urine output."]

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

Key facts at a glance

LOINC
15178-7
Short code
Comp Fact B Fld-mCnc
Synonyms
Comp Fact B Fld-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters

Creatinine clearance is a critical test for evaluating kidney function. Unlike simple blood tests, this method accounts for how much urine you produce in 24 hours, giving a more accurate picture of how efficiently your kidneys filter waste.

How the Test Works

Your urine is collected over 24 hours, and your blood is tested for creatinine levels. The test calculates how much creatinine passes through your kidneys and into your urine, reflecting kidney function.

What It Can Tell You

Low clearance may indicate kidney damage, poor blood flow, or conditions like diabetes or high blood pressure. High clearance could suggest overhydration or kidney issues that need further evaluation.

Common Uses

Doctors use this test to monitor kidney disease progression, check blood pressure treatment effectiveness, and assess kidney function before surgeries or treatments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Creatinine Clearance

Frequently asked questions

Why do I need this test?
Your doctor may order this test if you have symptoms like swelling, fatigue, or if you’re at risk for kidney problems (e.g., diabetes, high blood pressure, or a family history). It helps track how well your kidneys are working over time.
What should I expect during the test?
You’ll collect all your urine for 24 hours in a special container. Your blood will also be drawn for creatinine testing. It’s important to follow instructions precisely to get an accurate result.
Can I eat or drink normally before this test?
Yes, you can eat and drink as usual, but avoid excessive fluids if your doctor specifies. Follow any special instructions they provide to ensure accurate results.
  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