Skip to content

Hyaline Casts, Urine — Microscopy, Area Count

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

A urine microscopy test that measures hyaline casts, which are small structures formed in kidney tubules and often reported per low-power field.

Quick summary

["Hyaline casts in urine can occur with dehydration or exercise, but persistent or numerous casts may warrant evaluation for kidney disease."]

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

Key facts at a glance

LOINC
5796-8
Short code
Hyaline Casts #/area UrnS LPF
Synonyms
Hyaline Casts #/area UrnS LPF
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-lpf
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 under a microscope to identify and count hyaline casts. These casts are made of a protein called Tamm-Horsfall protein and are usually reported as an area or number per microscopic field.

Why might I need this test?

Urine cast examination may be used as part of a urinalysis or kidney evaluation. It can help identify changes associated with dehydration, strenuous exercise, medication use, or conditions that affect the kidneys.

How is the test performed?

A laboratory technician concentrates or spins a urine sample, places a small amount of sediment on a microscope slide, and examines it for casts and other formed elements. The result may be reported per low-power field or as an area count.

How do I prepare for the test?

No fasting or medication changes are usually required. Follow your clinician's instructions and provide a fresh urine sample in the specified clean-catch container when possible.

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?
They are tiny cylindrical structures made of a normal kidney protein. They can be found in urine during routine microscopic examination.
Do hyaline casts always mean kidney disease?
No. Dehydration, intense exercise, and some medications can increase them, and occasional findings may be normal. Persistent or substantial numbers are more concerning and require clinical interpretation.
Are other urine tests needed to interpret the result?
Yes. Findings are usually considered along with urine protein, blood, glucose, specific gravity, kidney function tests, symptoms, and other urine microscopy results.
  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