Skip to content

Creatinine Clearance (from 24-hour urine collection)

Published: August 9, 2026Updated: August 15, 2026

This test measures how well your kidneys filter waste products, specifically creatinine, over a full day. It helps assess kidney function and blood flow to the kidneys.

Quick summary

["A clear picture of kidney health and filtration efficiency over time."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
53047-7
Short code
CGA
Synonyms
CgA Fld-mCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube
Units
N/A
Ref low
0
Ref high
93
Fasting
false
Population
adult
Sex
all
Age range
18–99 years
Method
Enzyme-Linked Immunosorbent Assay (ELISA) or Chemiluminescent Immunoassay (CLIA)
CPT
86316
SNOMED
104136003
Specimen volume
1-2 mL of serum
Stability
Room temperature: 8 hours; Refrigerated (2-8°C): 48 hours; Frozen (-20°C or below): 3 months
Hemolysis max
100
Lipemia max
150
Icterus max
50
TAT
24–72 hours
Order
routine

Why This Test Matters

Creatinine clearance is a key indicator of kidney function. Unlike single-point measurements, this test provides a comprehensive view over 24 hours, reflecting long-term kidney performance. It’s particularly useful for diagnosing chronic kidney disease or monitoring kidney function in patients with conditions like diabetes or hypertension.

What to Expect Before the Test

You’ll collect all your urine over a 24-hour period, starting after you wake up the first morning. Empty your bladder at the start and discard the first urine. Seal all urine samples in a container and return them to the lab by the next morning. Drink plenty of fluids to ensure adequate urine production.

What Happens During the Test

No special preparation is needed beyond the urine collection. The lab will analyze the total creatinine in your urine and your blood creatinine level to calculate clearance. This involves simple blood and urine tests.

Possible Results and Interpretation

Results are compared to your body size (height and weight) and overall health. Lower than expected clearance may indicate kidney damage or disease, while higher values could suggest dehydration or overhydration. Your healthcare provider will discuss results in the context of your medical history.

Reference range

Generally <93 ng/mL in healthy adults; reference ranges vary by assay manufacturer. Elevated levels are commonly seen in neuroendocrine tumors.N/A

Specimen: serum

No special preparation required. Proton pump inhibitor (PPI) use should be documented as it may elevate Chromogranin A levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low creatinine clearance often signals kidney dysfunction, helping diagnose conditions like chronic kidney disease, glomerulonephritis, or other kidney-related disorders. It’s also used to monitor kidney function in patients on dialysis or with chronic illnesses like diabetes or heart disease. High clearance may prompt further investigation into fluid balance or other metabolic issues.

Short name

24-Hour Urine Creatinine Clearance

Frequently asked questions

How is creatinine clearance different from a single blood creatinine test?
A single blood creatinine test measures the current level of creatinine in your blood, while creatinine clearance assesses how well your kidneys filter creatinine over a full day. Clearance provides a more accurate long-term view of kidney function, as it accounts for urine production and volume.
Can I drink fluids during the 24-hour urine collection period?
Yes, but drink enough to produce about 600–800 mL (about 2–3 cups) of urine per hour. Avoid excessive fluid intake, as it may dilute the creatinine concentration and affect results. Your healthcare provider will give specific guidance based on your condition.
What if I miss collecting urine at the start or end of the 24-hour period?
If you miss the first or last urine collection, you’ll need to restart the 24-hour period. Discard the missed urine and begin collecting again from the next morning. Ensure you keep a record of all urine output to avoid gaps in the collection.
  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 15, 2026. · Read our editorial policy