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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 products from your blood, using a 24-hour urine sample and your serum creatinine level. It helps assess kidney function over time.

Quick summary

["A simple way to check how well your kidneys are working by tracking how efficiently they remove waste from your blood."]

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

Key facts at a glance

LOINC
22199-4
Short code
C trach C IgM Titr Ser
Synonyms
C trach C IgM Titr Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 key measure of kidney function because it reflects how well your kidneys filter waste products like creatinine from your blood. Unlike single-point measurements, this test provides a longer-term view of kidney performance.

How the Test Works

Your doctor will ask you to collect all urine over a 24-hour period. Blood is drawn to measure your serum creatinine level. The test compares how much creatinine appears in your urine versus how much remains in your blood to estimate how well your kidneys are filtering waste.

Preparation

No special preparation is needed for the blood draw, but you’ll need to collect all urine for 24 hours. Follow your doctor’s instructions carefully to ensure accurate results. Drink plenty of fluids to help with urine collection.

What to Expect

The blood draw is quick and typically done in a clinic or lab. The urine collection requires a 24-hour period, often with reminders to record every drop. Your doctor may provide a urine collection kit or instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Clearance

Frequently asked questions

Creatinine clearance helps detect early kidney problems before symptoms appear. Low levels may indicate kidney disease, while high levels could suggest dehydration or other conditions affecting kidney function.
This test is often used to monitor kidney function in people with diabetes, high blood pressure, or a history of kidney issues. It can also help guide treatment decisions for conditions like chronic kidney disease.
How often should I get this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and any kidney-related conditions. Regular monitoring may be recommended if you have risk factors for kidney disease.
What do my results mean?
Results are typically reported as a number (e.g., mL/min), which reflects your kidney function. A lower number may mean your kidneys aren’t filtering waste as well as they should, while a higher number could indicate overhydration or other factors. Always discuss your results with your healthcare provider.
  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