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Hemoglobin Casts, Urine — Microscopy

Published: August 9, 2026Updated: August 16, 2026

Microscopic examination of urine for hemoglobin casts, which may occur when red blood cells break down in the blood or urinary tract.

Quick summary

["Hemoglobin casts in urine can point to blood-cell breakdown, but results must be interpreted alongside the rest of the urinalysis and medical history."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
34174-3
Short code
Hgb Casts UrnS Ql Micro
Synonyms
Hgb Casts UrnS Ql Micro
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
10
Ref high
40
Critical range
7 N/A – 20 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 hemoglobin casts. These are small structures made when hemoglobin released from damaged red blood cells becomes trapped in a kidney tubule.

Why might I need this test?

A clinician may order urine microscopy when a urinalysis suggests bleeding or red blood cells in the urine. The test can help identify problems affecting the kidneys, urinary tract, or red blood cells.

How is the test performed?

A laboratory professional collects or receives urine, prepares it for microscopic examination, and looks for casts and other formed elements. Findings may be reported as present or absent, or with an amount, depending on the laboratory method.

How do I prepare for the test?

Follow any instructions provided by your clinician or laboratory. Often, a clean-catch urine sample collected at the laboratory is sufficient, and no special fasting or medication changes are required.

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 Hemoglobin Casts

Frequently asked questions

What are hemoglobin casts?
They are urine structures formed when hemoglobin from damaged red blood cells becomes trapped in a kidney tubule. They are identified through urine microscopy.
What does a positive result mean?
It means hemoglobin casts were detected in the urine. This can occur with red blood cell breakdown or certain kidney and urinary tract conditions and does not identify one cause by itself.
Is this the same as blood in the urine?
No. Blood in urine is generally described as a positive blood or red blood cell result, while this test specifically looks for hemoglobin casts under a microscope.
  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 16, 2026. · Read our editorial policy