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24-Hour Urinary Creatinine Clearance

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

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

Quick summary

["This test helps doctors check how well your kidneys are working and if blood is flowing properly to them."]

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

Key facts at a glance

LOINC
30875-9
Short code
MR UE joint
Synonyms
MR UE joint
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
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, poor blood flow to the kidneys, or other conditions affecting kidney function. It’s also used to evaluate kidney function in people with diabetes, high blood pressure, or other chronic health issues.

What to Expect Before the Test

You’ll need to collect all your urine for a full 24-hour period, typically starting and ending at the same time each day. Your doctor or lab technician will provide instructions on how to properly collect and store your urine samples. Blood may also be drawn on the same day to measure creatinine levels.

What Happens During the Test

After collecting your urine samples, the lab will analyze the urine for creatinine concentration. Blood creatinine levels are measured separately to calculate clearance. This process helps determine how efficiently your kidneys filter waste from your blood.

What the Results Mean

Clearance results are compared to standard values based on your age, sex, and body size. Low clearance may indicate kidney damage or disease, while high clearance could suggest overhydration or other conditions affecting kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24hr Urine Cr Clearance

Frequently asked questions

What does a 24-hour urine creatinine clearance test involve?
You’ll collect all your urine for a full 24-hour period, typically starting and ending at the same time each day. Blood may also be drawn on the same day to measure creatinine levels. This helps doctors assess kidney function accurately over time.
Why is blood drawn during this test?
Blood is drawn to measure creatinine levels, which are used alongside urine measurements to calculate how well your kidneys filter waste. This helps provide a more precise evaluation of kidney function compared to a single blood test alone.
Can I eat or drink normally before this test?
Yes, you can eat and drink as usual, but follow your doctor’s specific instructions for urine collection 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