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Waxy Casts, Urine — Microscopic Examination (Area Count)

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

Urine microscopy checks for waxy casts, which are cylindrical structures formed in the kidney. Their presence can be associated with longstanding or advanced kidney disease.

Quick summary

["Waxy casts in urine may signal advanced kidney damage but must be interpreted alongside other urine and kidney-function findings."]

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

Key facts at a glance

LOINC
5819-8
Short code
Waxy Casts #/area UrnS LPF
Synonyms
Waxy 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 a urine sample under a microscope to identify waxy casts. These casts are made of protein and cellular debris and may be reported as an area count.

Why might I need this test?

Urine microscopy may be ordered to evaluate possible kidney disease, especially when there are symptoms such as swelling, changes in urination, or abnormal kidney-function results.

How is the test performed?

A urine specimen is collected and examined microscopically for casts and other elements. The laboratory may process the urine sediment and report the amount of waxy casts observed.

How do I prepare for the test?

Follow your clinician's collection instructions, often using a clean-catch midstream sample. Fasting is generally not required, and the specimen should be provided as soon as possible after collection.

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 Waxy Casts

Frequently asked questions

What are waxy casts?
They are cylindrical urine structures made of compacted protein and cellular debris. They form within kidney tubules and are identified by microscopic examination.
Does finding waxy casts confirm kidney failure?
No. They may support a concern for advanced or chronic kidney disease, but they do not establish a diagnosis by themselves and require correlation with other clinical and laboratory findings.
Do I need to prepare for urine microscopy?
Usually, you simply need to collect urine as instructed and deliver it promptly. Your clinician will provide specific instructions if a first-morning, timed, or catheterized specimen is needed.
  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