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Creatinine Clearance (from Serum Urea/Nitrogen and Height)

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

This test helps measure how well your kidneys are filtering waste products from your blood, using your height and a blood test result (serum urea nitrogen).

Quick summary

["Assesses kidney function by estimating how efficiently your kidneys remove waste."]

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

Key facts at a glance

LOINC
36062-8
Short code
CT Should
Synonyms
CT Should
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.4
Ref high
4
Critical range
0.1 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
CPT
84443
SNOMED
301343003
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

What Is Creatinine Clearance Used For?

Creatinine clearance is primarily used to evaluate kidney function and diagnose or monitor kidney disease. It can also help determine how well your kidneys are working after treatments like dialysis or medications that affect kidney function.

How Is the Test Performed?

You’ll provide a blood sample (serum) and may also need to provide a 24-hour urine sample, though some tests may use a simplified method. Your height will be measured to calculate clearance. The lab will analyze the blood sample for urea nitrogen levels.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms of kidney problems (like fatigue, swelling, or frequent urination), if you have a chronic condition affecting your kidneys, or if you’re taking medications that can impact kidney function.

What to Expect Before the Test

No special preparation is usually needed for the blood test, but if you’re using a 24-hour urine collection, you’ll need to collect all urine for a full day. Avoid heavy exercise or dehydration before testing.

Reference range

Adult: 0.4-4.0 mIU/LN/A

Specimen: serum

Take your thyroid medication after the blood draw if applicable. No fasting required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Clearance

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time.
What does a low creatinine clearance mean?
A low creatinine clearance may indicate impaired kidney function, which could be due to chronic kidney disease, dehydration, or other conditions affecting kidney health.
Can diet affect creatinine clearance results?
Dietary protein intake can influence blood urea nitrogen levels, but creatinine clearance itself is less affected by diet. Still, high protein intake may slightly impact results, so your doctor may advise moderation if needed.
  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