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Myoglobin Casts, Urine — Qualitative, Microscopy

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

Looks for myoglobin-containing casts in urine using microscopy, which can help assess muscle breakdown and kidney injury.

Quick summary

["Detecting myoglobin casts in urine may indicate muscle breakdown affecting the kidneys."]

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

Key facts at a glance

LOINC
85096-6
Short code
Myoglobin casts UrnS Ql Micro
Synonyms
Myoglobin casts UrnS Ql Micro
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 200 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 urine test uses microscopy to look for myoglobin casts. Myoglobin is a protein released from damaged muscle, and casts are structures formed inside kidney tubules.

Why might I need this test?

The test may be ordered when muscle breakdown is suspected, especially with dark urine, muscle pain, weakness, or signs of kidney injury. It can also be used during monitoring of conditions or medicines that may injure muscle.

How is the test performed?

A urine specimen is collected and examined under a microscope to identify casts containing myoglobin. The result is reported as present or not present.

How do I prepare for the test?

Follow the laboratory's urine-collection instructions and tell the clinician if you have recently had intense exercise, muscle pain, or taken a medicine that may cause muscle breakdown. A fresh, clean-catch sample is usually requested.

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 Myoglobin Casts

Frequently asked questions

What are myoglobin casts?
They are kidney-tubule casts that contain myoglobin, a muscle-derived protein. Their presence may indicate muscle breakdown and possible kidney involvement.
Does exercise cause a positive result?
Strenuous exercise can sometimes cause temporary muscle injury and myoglobin in the urine. The clinical context helps distinguish this from more significant muscle damage.
Is this the same as a urine myoglobin test?
No. This test specifically identifies myoglobin-containing casts by microscopy, whereas a urine myoglobin test measures myoglobin itself. The laboratory may use both 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