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Broad Casts, Urine — Semi-Quantitative Microscopy

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

A urine microscopy test that identifies broad, waxy casts in a urine sample. Results are interpreted with kidney function tests and the rest of the urinalysis.

Quick summary

["Broad casts can be a sign of reduced urine flow or impaired kidney function, but the result must be interpreted with the rest of your urine and kidney tests."]

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

Key facts at a glance

LOINC
31999-6
Short code
Broad Casts UrnS Ql Micro
Synonyms
Broad 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 under a microscope to look for broad casts, also called waxy casts. These structures form inside the kidney's urine-collection tubes.

Why might I need this test?

Urine microscopy may be ordered during a urinalysis, when evaluating kidney function, or when symptoms suggest a urinary tract or kidney condition. It can also help assess the flow of urine through the kidneys.

How is the test performed?

A laboratory examines a urine sample under a microscope and reports whether broad casts are present and, when applicable, their relative amount. No blood draw is required.

How do I prepare for the test?

Follow your clinician's urine-collection instructions, which may include collecting a clean-catch midstream sample. Use the provided container and deliver the sample promptly as directed.

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 broad casts

Frequently asked questions

What are broad casts?
Broad casts are waxy structures that form inside kidney tubules and can be seen during urine microscopy. They are commonly referred to as waxy casts.
Do broad casts mean I have kidney failure?
No. Broad casts can suggest reduced urine flow or impaired kidney function, but they cannot diagnose kidney failure by themselves. Your clinician will interpret them with other laboratory results and your overall health.
Do I need special preparation for this test?
Usually, you only need to follow the urine-collection instructions provided by the laboratory or clinician. Proper collection and timely delivery help produce a reliable result.
  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