Skip to content

Crystals and Casts, Urine — Semi-quantitative Microscopy

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

Microscopic examination of a urine sample to identify and semi-quantify crystals and casts that can help evaluate kidney and urinary conditions.

Quick summary

["This urine microscopy test checks for crystals and casts that may reflect hydration, medications, metabolic changes, or kidney disease."]

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

Key facts at a glance

LOINC
85093-3
Short code
Crystal casts UrnS Ql Micro
Synonyms
Crystal 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 identify crystals and casts. Crystals are solid substances that form in urine, while casts are small structures made inside the kidney's microscopic tubules.

Why might I need this test?

This test may be ordered as part of a urinalysis, particularly when there are symptoms such as painful urination, blood in the urine, frequent urination, or changes in urine color. It can also help monitor kidney conditions, kidney stones, or the effects of certain medications.

How is the test performed?

A urine specimen is collected and reviewed by a laboratory professional using microscopy. The laboratory reports the types and relative amounts of any crystals and casts observed.

How do I prepare for the test?

Follow the laboratory's urine-collection instructions, which may include providing a clean-catch, midstream urine sample. The sample should be collected in the supplied container and delivered 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 crystals and casts

Frequently asked questions

Does finding crystals in urine always mean I have kidney stones?
No. Crystals can be found without symptoms or stones, especially with concentrated urine or certain medication and metabolic changes. Their significance depends on the type and amount, along with symptoms and other laboratory results.
What do urine casts indicate?
Casts form inside the kidney tubules. Certain types can be associated with kidney inflammation, injury, or other kidney conditions, while others may be temporary and not clinically significant.
Can I influence the results by how I collect my urine?
Yes. A clean-catch midstream sample and prompt delivery help reduce contamination and changes that can affect microscopic findings. Follow the specific instructions provided by the laboratory.
  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