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Understanding Your Medical Test: What It Is, How It Is Performed, and Why Your Doctor Ordered It

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

Acanthocytes in urine sediment by Light microscopy is a test that detects abnormal red blood cells in urine, which may indicate kidney or urinary tract problems.

Quick summary

{"Acanthocytes (also called burr cells) are red blood cells with a spiky, irregular shape found in urine","This test helps doctors diagnose kidney diseases, urinary tract disorders, or certain blood disorders","A small number may be normal, but high levels usually require further investigation","The test is performed on a urine sample examined under a microscope","Results help determine if additional tests or treatment are needed"}

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

Key facts at a glance

LOINC
91135-4
Short code
ACAN-UR
Synonyms
Acanthocytes UrnS Ql Micro
Category
chemistry
Sample
urine
Container
Sterile, graduated urine container (plastic, screw-top, 100 mL capacity)
Units
N/A
Ref low
0
Ref high
2
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
microscopy-light
CPT
81001
SNOMED
271587006
Specimen volume
10-20 mL minimum; 50-100 mL preferred
Stability
Room temperature (20-25°C): analyze within 2 hours of collection. Refrigerated (2-8°C): stable for up to 24-48 hours. Do not freeze. Protect from prolonged light exposure.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
1–4 hours
Order
routine

What is this test and what does it measure? This test gives your healthcare team important information about how your body is working, helping to explain symptoms you may have and guide decisions about your care.

The Acanthocytes (Burr Cells) in Urine test is a microscopic examination of urine sediment to detect the presence of acanthocytes. Acanthocytes are red blood cells that have an abnormal, spiky or burr-shaped appearance due to uneven membrane surfaces. Under a light microscope, these cells appear with irregular, thorn-like projections around their edges. This test is part of a routine urinalysis and helps healthcare providers identify underlying medical conditions affecting the kidneys or urinary tract.

How is the test performed? A trained healthcare professional will collect the needed sample, such as blood, urine, or tissue, using a safe and routine procedure, and the sample is then sent to a laboratory for analysis.

A urine sample is collected, typically in a sterile container. The sample is then centrifuged to separate the solid particles (sediment) from the liquid. The sediment is examined under a light microscope by a laboratory technician or pathologist, who identifies and counts the number of acanthocytes present. The result is usually reported as either 'present' or 'absent,' though sometimes a semi-quantitative scale (such as 'rare,' 'few,' 'moderate,' or 'many') may be used.

Why is this test ordered? Your doctor may order this test to help diagnose a medical condition, monitor an ongoing illness, check how well a treatment is working, or screen for potential health problems before symptoms appear.

This test is commonly ordered as part of a routine urinalysis, especially when a patient has symptoms such as blood in urine (hematuria), painful urination, flank pain, swelling (edema), or unexplained protein in urine. It helps differentiate between various types of urinary abnormalities and guides further diagnostic workup.

Reference range

Acanthocytes not typically present in significant numbers. Reference range: None seen or <2% of total RBCs observedN/A

Specimen: urine

Collect clean-catch midstream urine sample. Female patients should clean perineum from front to back. Avoid contamination with vaginal discharge or menstrual blood. Inform clinician of menstrual status.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Is this test painful?
No, the test itself is not painful. It simply requires providing a urine sample, which is a routine and non-invasive procedure.
Do I need to fast before this test?
No special preparation or fasting is typically required for this test. However, it is best to follow any specific instructions provided by your healthcare provider.
What do the results mean?
A 'negative' or 'absent' result means no acanthocytes were detected, which is generally considered normal. A 'positive' or 'present' result indicates the presence of abnormal red blood cells and may require further investigation. Your healthcare provider will interpret the results in context with your symptoms and other test findings.
Will I need additional tests if acanthocytes are found?
Yes, if acanthocytes are detected, your doctor may order additional tests such as blood tests, kidney function tests, imaging studies (like ultrasound or CT scan), or a kidney biopsy to determine the underlying cause.
Can certain medications affect this test?
Yes, some medications such as anticoagulants (blood thinners), aspirin, or certain antibiotics may affect urine findings. Inform your healthcare provider about all medications you are taking before the test.
  1. 1
    MedlinePlus - UrinalysisSource
  2. 2
    Mayo Clinic Laboratories - Urine MicroscopySource
  3. 3
    National Kidney Foundation - UrinalysisSource

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