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Urine Casts, Microscopic Examination (per High-Power Field)

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

A urine microscopy test that counts microscopic structures called casts. The results may help evaluate kidney conditions and hydration status.

Quick summary

["Urine cast results are interpreted alongside urine findings, symptoms, and kidney function to help assess kidney health."]

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

Key facts at a glance

LOINC
9439-1
Short code
Casts #/area UrnS HPF
Synonyms
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 under a microscope to identify and count casts. Casts are structures formed in the kidney's microscopic urine tubes, called tubules.

Why might I need this test?

A clinician may order urine cast analysis as part of a urinalysis, kidney evaluation, or investigation of symptoms such as swelling, changes in urination, or unexplained abnormalities in urine tests.

How is the test performed?

The urine is spun in a centrifuge, and the material left at the bottom is examined under a microscope. Casts are identified and reported per high-power field, a standardized microscope viewing area.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional. A clean-catch midstream urine sample is often requested, and testing may be delayed for a short period after collection, so prompt delivery is important.

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 casts

Frequently asked questions

What are urine casts?
Urine casts are small structures that form when proteins and other materials collect inside kidney tubules and are flushed into the urine. Different types can be associated with different clinical conditions.
Does finding urine casts always mean I have kidney disease?
No. Casts may occasionally occur in healthy urine, especially during dehydration, and they are interpreted together with the rest of the urinalysis and your clinical situation.
What information should I bring to my appointment?
Bring the full laboratory report and information about any symptoms, medications, recent illness, and changes in urination. Your clinician can explain how the cast result fits with your other kidney tests.
  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