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Hyaline Casts, Urine — Qualitative Microscopy

Published: August 9, 2026Updated: August 17, 2026

Microscopic examination of urine for hyaline casts, which are small structures formed in the kidney's urine-filtering tubules.

Quick summary

["Hyaline casts in urine may be normal but can also occur with dehydration or kidney tubular injury."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
25162-9
Short code
Hyaline Casts UrnS Ql Micro
Synonyms
Hyaline Casts UrnS Ql 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 urine sediment under a microscope to look for hyaline casts. These are cylindrical structures made of proteins and formed inside the kidney's filtering tubules.

Why might I need this test?

Urine cast examination may be included as part of a urinalysis, particularly when a clinician is evaluating kidney function, urinary symptoms, or suspected kidney injury.

How is the test performed?

A urine specimen is collected and prepared for microscopic examination. A laboratory professional looks at the concentrated urine sediment to identify and report the types of casts present.

How do I prepare for the test?

Follow your clinician's or laboratory's urine-collection instructions, often including a clean-catch midstream sample. Tell the laboratory if you exercised heavily or have recently received certain medications, because these can affect urine findings.

Reference range

Adult: 10-40 U/LN/A

Specimen: urine

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine Hyaline Casts

Frequently asked questions

What are hyaline casts?
Hyaline casts are small, transparent protein structures that form in the kidney's urine-filtering tubules. They are identified by microscopic examination of urine sediment.
Does finding hyaline casts always mean kidney disease?
No. They may occur in healthy people, particularly after exercise or when urine is concentrated. Interpretation depends on the number of casts and other clinical and laboratory findings.
What other information should I review with my results?
Ask your clinician to review the complete urinalysis, including protein, blood, and other microscopic findings, along with kidney function tests and your symptoms.
  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 17, 2026. · Read our editorial policy