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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 combination of your blood and urine samples over 24 hours.

Quick summary

["Assesses kidney function by estimating how efficiently your kidneys remove creatinine from your blood."]

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

Key facts at a glance

LOINC
59643-7
Short code
Cocaethylene SerPl Cfm-mCnc
Synonyms
Cocaethylene SerPl Cfm-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
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 for kidney disease, monitor kidney function in chronic conditions (like diabetes or high blood pressure), or evaluate kidney damage before certain procedures. It helps determine how well your kidneys are working to remove waste products from your blood.

How the Test Works

Your blood is drawn to measure creatinine levels. Separately, a 24-hour urine sample is collected to measure creatinine excretion. The test calculates clearance by comparing these values to your body’s size (weight).

Sample Requirements

You’ll need two separate collections: a blood sample (taken at one time) and a full 24-hour urine sample (starting after your first morning urine). Follow your doctor’s instructions carefully to ensure accurate results.

What to Expect

Blood draw is quick and usually done at a lab or doctor’s office. For the urine collection, you’ll need to collect every drop of urine for 24 hours, discarding the first morning urine and saving the rest in a container. Drink plenty of water to help your kidneys work properly during this time.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Clearance

Frequently asked questions

What does a low or high creatinine clearance mean?
A lower than expected clearance may indicate kidney damage or disease, while a higher clearance could suggest overhydration or kidney dysfunction (e.g., polycystic kidney disease). Always discuss results with your healthcare provider, as they’ll consider your overall health and medical history.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. For example, people with diabetes or chronic kidney disease may need it more frequently than others.
Can I eat or drink anything before this test?
No special diet is needed for the blood test, but for the urine collection, drink as much water as you normally would to ensure proper urine volume. Avoid excessive caffeine or alcohol before testing, as they may affect 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