Hyaline Casts, Urine — Microscopic Examination
This urine microscopy test detects hyaline casts, cylindrical structures formed in the kidney's small filtering tubules.
["Hyaline casts in urine are a nonspecific finding and must be interpreted with symptoms and other kidney test results."]
Key facts at a glance
- LOINC
- 46135-0
- Short code
- Hyaline Casts #/area UrnS HPF
- Synonyms
- Hyaline Casts #/area UrnS HPF
- 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-hpf
- 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 for hyaline casts. These are small cylindrical structures made of proteins that can form inside the kidney's filtering tubules and then pass into the urine.
Why might I need this test?
Urine cast examination may be included as part of a urinalysis, especially when evaluating kidney inflammation, dehydration, or possible kidney injury. It can also help assess the cause of abnormal urine findings.
How is the test performed?
A urine specimen is examined using microscopy, sometimes with an automated urine-sediment analyzer. The laboratory may report the amount of hyaline casts observed per microscopic field, depending on the laboratory's method.
How do I prepare for the test?
Follow your laboratory's urine-collection instructions. A clean-catch, midstream urine sample is usually requested, and the sample should be tested as soon as possible. Tell the laboratory if you are taking medicines that may affect urine findings.
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.
A small number of hyaline casts can occur normally, particularly after exercise or with dehydration. Larger amounts may be associated with reduced urine flow, concentrated urine, or kidney conditions, but this finding alone does not diagnose a specific disorder. Results should be interpreted with other urinalysis findings, kidney tests, symptoms, and medical history.
Short name
Urine hyaline casts
Frequently asked questions
What are hyaline casts?
Does finding hyaline casts mean I have kidney disease?
Can this test be performed at home?
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