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Urinalysis with Microscopic Examination for Red Blood Cells, White Blood Cells, and Casts

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

This test examines your urine under a microscope to check for blood cells, white blood cells, or abnormal shapes (casts) that may signal kidney or urinary tract issues.

Quick summary

["Microscopic urine analysis helps detect hidden problems in your urinary system."]

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

Key facts at a glance

LOINC
44973-6
Short code
QRS dur {EKG lead}
Synonyms
QRS dur {EKG lead}
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does the Microscope Look For?

Red blood cells (RBCs) in urine can indicate bleeding in the kidneys, bladder, or urethra. White blood cells (WBCs) may suggest infection or inflammation. Casts are protein-based structures that can reveal kidney damage or disease.

Common Causes of Findings

Positive results for RBCs or WBCs often point to infections (like UTIs), kidney stones, or other urinary tract issues. Casts may appear with conditions like glomerulonephritis or diabetic nephropathy.

When Might This Test Be Ordered?

Your doctor may recommend this test if you have symptoms like pain during urination, blood in urine, frequent urination, or if you’re experiencing general kidney-related concerns.

What to Expect During the Test

You’ll provide a urine sample (usually a midstream clean-catch or catheterized sample). The lab then examines it under a microscope for cells, casts, or crystals.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for diagnosing urinary tract infections, kidney diseases, or structural abnormalities. Early detection can guide treatment and prevent complications.

Short name

Urine Microscopy

Frequently asked questions

Why do I need this test?
Your doctor may order it to check for hidden urinary issues, monitor kidney health, or investigate symptoms like pain, blood in urine, or frequent urination.
What does a positive result mean?
Positive findings (like RBCs or WBCs) often mean an infection, inflammation, or kidney problem. Your doctor will discuss next steps based on the specific results and your symptoms.
How often should I get this test?
Frequency depends on your health status. Routine checks may be recommended if you have kidney disease, diabetes, or a history of urinary issues; otherwise, it’s usually ordered as needed.
  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