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Waxy Casts, Urine Sediment — Microscopy

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

A urine microscopy test that looks for waxy casts, which may be associated with long-standing kidney disease or dehydration.

Quick summary

["Waxy casts in urine can suggest reduced kidney function, but the result must be interpreted with other urine and blood tests."]

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

Key facts at a glance

LOINC
33862-4
Short code
Waxy Casts UrnS Ql Micro
Synonyms
Waxy 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 a urine sample under a microscope to look for waxy casts. These structures form inside kidney tubules and may occasionally be released into the urine.

Why might I need this test?

A clinician may order urine microscopy as part of a kidney or urinary tract evaluation, particularly when there are symptoms such as swelling, changes in urination, or unexplained changes in kidney function.

How is the test performed?

The urine is processed in the laboratory, and a portion of the sediment is examined with a microscope. The laboratory reports whether waxy casts are identified.

How do I prepare for the test?

Usually no special preparation is required, but follow any collection instructions from your healthcare professional. A clean-catch urine sample is typically requested and should be delivered promptly.

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

Are waxy casts the same as granular casts?
No. Waxy casts have a smooth, waxy appearance and are distinct from granular casts, although both can appear in urine sediment.
Does finding waxy casts confirm kidney failure?
No. They may support concern for advanced kidney dysfunction, but the finding alone does not diagnose kidney failure or determine its cause.
Can dehydration cause waxy casts?
Yes. Severe dehydration can sometimes be associated with waxy casts, so your clinician will consider hydration status and other test 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