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Bburgdor39kdigmsnvqlib

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

This test detects IgM antibodies against the Lyme disease bacterium in joint fluid to help diagnose Lyme arthritis.

Quick summary

{"This test looks for Lyme disease antibodies in joint fluid","IgM antibodies are usually the first ones your body makes to fight a new infection","A positive result suggests you may have Lyme arthritis","The test uses immunoblot technology to detect specific bacterial proteins","Joint fluid is collected using a needle (arthrocentesis)"}

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

Key facts at a glance

LOINC
30020-2
Short code
BB39IGMSF
Synonyms
B burgdor39kD IgM Snv Ql IB
Category
chemistry
Sample
fluid
Container
Sterile, screw-capped, leak-proof container without preservative; cryovial preferred for immunoblot testing
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoblot (Western Blot)
CPT
86617
SNOMED
39512009
Specimen volume
1-2 mL synovial fluid
Stability
Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days; Avoid repeated freeze-thaw cycles
Hemolysis max
300
TAT
48–96 hours
Order
routine

What is this test?

This test checks for IgM antibodies against the 39kD protein of Borrelia burgdorferi (the bacterium that causes Lyme disease) in your joint fluid. The test uses a method called immunoblot (also known as Western blot) to detect these specific antibodies. IgM antibodies are typically the first antibodies your immune system produces when fighting a new infection.

Why is this test done?

This test is primarily used to diagnose Lyme arthritis, which is a complication of Lyme disease that affects the joints. When you have Lyme disease and the bacteria spread to your joints, your body produces antibodies against the bacteria. Testing the joint fluid directly can help confirm whether the joint inflammation is caused by Lyme disease.

How is the sample collected?

A healthcare provider will collect fluid from your affected joint using a thin needle. This procedure is called arthrocentesis or joint aspiration. The area will be cleaned and numbed to minimize discomfort. The fluid is then sent to a laboratory for testing.

What do the results mean?

A positive result indicates that IgM antibodies against the 39kD protein of Borrelia burgdorferi were detected in your joint fluid. This strongly suggests that your joint inflammation is due to Lyme disease arthritis. A negative result does not completely rule out Lyme disease, as the test may be negative early in infection or if the infection has been treated.

Reference range

Negative: No antibodies to Borrelia burgdorferi 39kD antigen detected. Positive: Antibodies to Borrelia burgdorferi 39kD antigen detected, consistent with recent or active infection.N/A

Specimen: fluid

No special patient preparation required. Specimen is collected via arthrocentesis (joint aspiration) by a qualified healthcare professional under aseptic technique.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Is this test painful?
The joint aspiration procedure may cause some discomfort or pressure, but the area is typically numbed with local anesthetic to minimize pain. You may feel some soreness in the joint for a day or two after the procedure.
How long does it take to get results?
Immunoblot tests are specialized and typically take 3-7 days to complete. Your healthcare provider will contact you with the results once they are available.
Do I need to fast before this test?
No fasting is required for this test. You can eat and drink normally before the procedure.
What happens if the test is positive?
If the test is positive, your healthcare provider will likely recommend antibiotic treatment for Lyme arthritis. The typical treatment is a 2-4 week course of oral or intravenous antibiotics. Early treatment is important to prevent long-term joint damage.
Can this test be done on blood instead of joint fluid?
Yes, blood tests for Lyme disease antibodies are more commonly performed. However, testing synovial fluid can be more helpful when the diagnosis is uncertain or when joint symptoms persist despite treatment. Your doctor will determine which test is most appropriate for your situation.
  1. 1
    CDC - Lyme Disease Diagnosis and TestingSource
  2. 2
    Mayo Clinic - Lyme DiseaseSource

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