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Creatinine Clearance (Serum-Based, 24-Hour Urine Collection)

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

This test measures how well your kidneys filter waste from your blood, using a 24-hour urine sample and a blood sample. It helps assess kidney function and blood flow.

Quick summary

["A key measure of kidney health and blood filtration efficiency."]

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

Key facts at a glance

LOINC
43548-7
Short code
Deprecated Finger.4th-R XR GE 3V
Synonyms
Deprecated Finger.4th-R XR GE 3V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 It’s Done

Your doctor may order this test if you have symptoms of kidney problems, such as swelling, frequent urination, or fatigue. It’s also used to check kidney function before certain surgeries, treatments, or if you have conditions like diabetes or high blood pressure that can affect kidneys.

How It Works

A blood sample is taken to measure creatinine levels. A 24-hour urine sample is collected to measure creatinine and urine volume. The test calculates how much creatinine is filtered out of your blood over time.

Sample Collection

You’ll need to collect all urine for a full 24-hour period (from one morning to the next morning). Your doctor or lab technician will provide instructions. A simple blood draw is also required on the same day.

Potential Side Effects

Most people experience mild discomfort from the blood draw. Collecting urine over 24 hours may require reminders to stay hydrated and empty your bladder completely at scheduled times.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Clearance

Frequently asked questions

How long does the 24-hour urine collection take?
The urine collection period lasts exactly 24 hours. You’ll need to carefully track your urine output, keeping all samples in a container provided by the lab until it’s returned for testing.
Can I drink alcohol during the urine collection?
Alcohol is generally fine, but excessive amounts may affect urine volume or creatinine levels. Stick to your usual hydration habits unless instructed otherwise by your doctor.
What if I miss a urine sample during the 24-hour period?
If you miss any urine, you’ll need to start over with a fresh 24-hour collection. Your doctor may also ask for a shorter or alternative test if the full collection isn’t possible.
  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