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Urea Nitrogen and Creatinine, Urine

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

Measures urea nitrogen and creatinine in urine to help assess kidney function, urine concentration, and how the body is handling protein breakdown.

Quick summary

["This urine test can help evaluate kidney function and hydration, especially when interpreted alongside other findings."]

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

Key facts at a glance

LOINC
44416-6
Short code
UUN/Creat Ur
Synonyms
UUN/Creat Ur
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test measures two waste products in urine: urea nitrogen, which forms when the body breaks down protein, and creatinine, which forms from muscle activity. The results can provide information about kidney function and how concentrated the urine is.

Why might I need this test?

A clinician may order this test to evaluate kidney function, investigate changes in urine output, assess hydration, or monitor an existing kidney condition. It may also be used with other tests when evaluating how the body handles protein and other nutrients.

How is the test performed?

A urine sample is collected and analyzed in the laboratory for urea nitrogen and creatinine. The report may show the measurements separately or together as a ratio, depending on the test ordered and the laboratory method.

How do I prepare for the test?

Follow the collection instructions provided by your clinician or laboratory. If a timed or 24-hour collection is requested, collect all urine for the specified period and record the collection time; otherwise, a single urine sample may be used.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Urine urea nitrogen and creatinine are affected by urine concentration, hydration, protein intake, muscle mass, and kidney function. Results that are unexpectedly high or low may reflect dehydration, dilute urine, kidney impairment, or other clinical and dietary factors. The results should be interpreted with the collection method, other laboratory tests, and your medical history.

Short name

Urine urea nitrogen and creatinine

Frequently asked questions

Do I need to fast for this test?
Fasting is usually not required, but follow any specific instructions from your clinician. A high-protein meal or unusual fluid intake can affect the results.
Does this test diagnose kidney disease by itself?
No. This test can provide useful information about kidney function and urine concentration, but a diagnosis usually requires additional symptoms, examination findings, and other laboratory tests.
Why is it important to complete the entire urine collection?
If a timed collection is ordered, missing urine or collecting it for the wrong period can make the results inaccurate. Follow the laboratory's timing and storage instructions carefully.
  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