Urinary Casts, Microscopic Examination
A urine microscopy test that looks for casts, which are small structures formed in the kidney tubules and can provide information about hydration and kidney health.
["Urinary casts can offer clues about hydration, kidney injury, or kidney disease when interpreted with the rest of your urine test."]
Key facts at a glance
- LOINC
- 58436-7
- Short code
- Casts UrnS Micro
- Synonyms
- Casts UrnS Micro
- Category
- liver
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- microscopy-light
- CPT
- 84484
- SNOMED
- 302774002
- 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 examines a urine sample under a microscope to look for casts. Casts are small, tube-shaped structures that form inside the kidney tubules and are released into the urine.
Why might I need this test?
A clinician may order urine microscopy to evaluate possible kidney problems, especially when there are symptoms such as swelling, reduced urination, blood in the urine, or unexplained changes in kidney function. It may also be used to assess dehydration or monitor certain illnesses and medicines.
How is the test performed?
A urine sample is collected and examined under a microscope. The laboratory looks for casts and may report their type and amount, along with other microscopic findings.
How do I prepare for the test?
Follow the collection instructions provided by your healthcare professional. In many cases, a clean-catch midstream urine sample is requested, and the first urine of the day should not be used unless specifically instructed.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Urinary casts can occur with dehydration or concentrated urine. Certain types may be associated with kidney injury, inflammation, infection, or other kidney conditions, but casts alone do not establish a diagnosis. Results should be interpreted by a clinician together with symptoms, other urine findings, and kidney function tests.
Short name
Urinary casts
Frequently asked questions
What does it mean if casts are found in my urine?
Does finding urinary casts mean I have kidney failure?
Can I use a home urine test instead?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 17, 2026. · Read our editorial policy