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Creatinine Clearance (Calculated from Serum Creatinine and Urine Creatinine)

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

This test measures how well your kidneys are filtering waste products from your blood. It uses results from both your blood and urine to estimate kidney function.

Quick summary

["Assesses kidney function by calculating how efficiently your kidneys remove waste through urine."]

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

Key facts at a glance

LOINC
36032-1
Short code
XR tomo Kidney
Synonyms
XR tomo Kidney
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-tomography
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 helps doctors determine if your kidneys are working properly. It’s especially useful for monitoring kidney disease, managing medications that affect kidney function, and checking for early signs of kidney problems.

How the Test Works

Your blood is tested for creatinine levels, and your urine is collected over a set period (often 24 hours) to measure creatinine excretion. The test calculates how much creatinine your kidneys filter out of your blood.

What to Expect Before the Test

No special preparation is needed for blood testing, but for urine collection, you may need to collect all urine for a full 24-hour period. Drink plenty of water to help your kidneys produce urine normally.

What the Results Mean

Results are typically reported as a clearance rate (e.g., milliliters per minute or milliliters per hour). Lower than expected values may indicate kidney problems, while higher values could suggest overhydration or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Clearance

Frequently asked questions

What causes creatinine clearance to be low?
Low creatinine clearance can be caused by kidney disease, dehydration, heart failure, or conditions that restrict blood flow to the kidneys. It may also be influenced by medications or underlying health conditions that affect kidney function.
What should I do if my creatinine clearance is abnormal?
If your results are below normal, your doctor may recommend further testing, adjustments to your medications, or lifestyle changes to support kidney health. Follow their guidance closely and report any symptoms like swelling, fatigue, or changes in urine output.
Can diet affect creatinine clearance results?
Yes, diet can influence creatinine levels. High-protein diets may temporarily increase creatinine in the blood, while dehydration can lower clearance. Staying hydrated and discussing your diet with your healthcare provider can help 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