POLARIZING MICROSCOPY BODY FLUIDS – HS52
🔬 Gout & Crystal AnalysisThis test is usually performed on Synovial (Joint) Fluid. This sample must be collected by a doctor (Orthopedist/Rheumatologist) via aspiration. You must bring the collected fluid to the lab.
📋 Test Details
- Report Time: Next Day Evening.
- Method: Polarized Light Microscopy.
- Sample Type: Body Fluid (Synovial, Pleural, or Peritoneal).
- Test Code: HS52
What is Polarizing Microscopy?
This is a specialized microscopic technique used to identify materials that are birefringent (they shine or change color under polarized light). In medicine, its primary use is to analyze Synovial Fluid (the fluid found inside joints like the knee, elbow, or toe) to detect microscopic crystals.
When a patient has a swollen, red, and painful joint, doctors order this test to distinguish between different types of Arthritis.
Why is this Test Prescribed?
It is the Gold Standard for diagnosing crystal-induced arthritis. It differentiates between two main conditions:
Under polarized light, Uric Acid crystals appear as Needle-shaped and show Negative Birefringence (Yellow when parallel to the light). This confirms a Gout attack.
Caused by Calcium Pyrophosphate crystals. They appear Rhomboid-shaped (rectangular) and show "Positive Birefringence" (Blue when parallel). This requires different treatment than Gout.
Other Uses
While most common for joints, it can also be used on:
- Urine: To identify specific lipid crystals (Maltese Cross pattern) in Nephrotic Syndrome.
- Pleural/Ascitic Fluid: To check for rare cholesterol crystals.
Frequently Asked Questions
No. A blood test measures uric acid in your circulation. This test looks for actual crystals inside the joint fluid. This is much more accurate for diagnosing an acute attack.
No. Synovial fluid must be extracted by a specialized doctor using a sterile needle (arthrocentesis). You cannot collect this yourself.
The fluid needs to be processed carefully on slides and examined manually by a skilled pathologist under a polarized microscope to ensure no crystals are missed.
Disclaimer: This test aids in diagnosis. Clinical correlation by a Rheumatologist or Orthopedist is required.