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24-Hour Urine Collection for Creatinine Clearance

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

This test measures how well your kidneys filter waste products from your blood over a full day. It involves collecting all urine for 24 hours to assess kidney function.

Quick summary

["Helps check how well your kidneys are working by tracking waste removal over time."]

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

Key facts at a glance

LOINC
27490-2
Short code
DATERANGE
Synonyms
—
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 Is Done

Doctors may order this test to evaluate kidney function, diagnose kidney disease, or monitor chronic conditions like diabetes or high blood pressure. It helps determine how efficiently your kidneys clear waste products like creatinine from your blood.

How the Test Works

You’ll need to collect all urine produced in a 24-hour period in a special container. The urine is then sent to the lab for analysis to calculate creatinine clearance, which reflects kidney function.

Sample Collection Process

You’ll start the collection right after midnight (or as directed by your doctor). Empty your bladder first, then collect every drop of urine for the next 24 hours. Store the urine in a cool place and keep the container clean. Do not miss any urine—this test requires a full 24-hour period.

What to Expect Before the Test

No special preparation is needed, but you should drink enough water to maintain normal urine output. Avoid excessive alcohol or certain medications that may affect kidney function. Follow your doctor’s instructions carefully to ensure accurate results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

None

Frequently asked questions

This test is critical for diagnosing kidney-related issues, such as chronic kidney disease, kidney stones, or other conditions affecting urine production. Low clearance may indicate kidney damage, while high clearance could signal overhydration or other metabolic issues.
A 24-hour urine creatinine clearance test helps doctors assess kidney function by measuring how well your kidneys filter waste products over time. It’s particularly useful for detecting early kidney problems that might not show up in single blood tests.
What does a low creatinine clearance mean?
A low creatinine clearance suggests your kidneys may not be filtering waste products efficiently, which could indicate kidney disease, damage, or other underlying conditions like diabetes or hypertension.
How long does it take to get results?
Results typically take 1–3 business days, depending on lab processing times. Your doctor will discuss the findings with you during your follow-up appointment.
  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