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Borrelia burgdorferi Antibody Immunoblot on Synovial Fluid (Lyme Disease Test)

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

This test detects antibodies against Borrelia burgdorferi (the bacterium that causes Lyme disease) in joint fluid using immunoblot technique.

Quick summary

{"The test looks for immune response to Lyme disease bacteria in joint fluid","A positive result suggests Lyme arthritis (joint involvement in Lyme disease)","The test uses immunoblot method to detect specific antibodies","Synovial fluid is collected from the affected joint by aspiration","Results are interpreted as positive, negative, or indeterminate"}

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

Key facts at a glance

LOINC
44020-6
Short code
LYMESYNWB
Synonyms
B burgdor Ab Snv Ql IB
Category
chemistry
Sample
fluid
Container
Sterile, leak-proof, screw-cap container (plain, no anticoagulant); alternatively, sterile collection tube for synovial fluid analysis
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoblot (Western Blot)
CPT
86617
SNOMED
1087191000119102
Specimen volume
Minimum 1-2 mL of synovial fluid
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
Hemolysis max
300
TAT
48–168 hours
Order
routine

What is the Borrelia burgdorferi immunoblot test on synovial fluid?

The Borrelia burgdorferi Antibody Immunoblot test detects whether your immune system has produced antibodies against the bacteria that cause Lyme disease. Unlike blood tests, this test analyzes synovial fluid (the fluid that lubricates your joints) to determine if Lyme disease has affected a specific joint.

What is Borrelia burgdorferi and how is it related to Lyme disease?

Borrelia burgdorferi is a spirochete (spiral-shaped) bacterium transmitted through the bite of infected blacklegged ticks (Ixodes scapularis). In the United States, this bacterium causes Lyme disease, which can affect the skin, joints, nervous system, and heart if left untreated.

What is synovial fluid and why is it tested for Borrelia burgdorferi antibodies?

Synovial fluid is a thick, slippery liquid that cushions and lubricates the joints. When Lyme disease spreads to the joints, it can cause inflammation and swelling. Analyzing this fluid helps doctors confirm whether Lyme bacteria are present in the joint itself.

How does the immunoblot test detect Borrelia burgdorferi antibodies in joint fluid?

Immunoblot (also called Western blot) is a laboratory technique that detects specific proteins (antigens) from the Borrelia burgdorferi bacterium. The test identifies whether your immune system has created antibodies against multiple bacterial proteins. A positive pattern of specific bands indicates exposure to the Lyme disease bacterium.

Why might I need a Borrelia burgdorferi immunoblot test of my joint fluid?

Your doctor may order this test if you have symptoms of Lyme arthritis, such as joint swelling (typically in the knee), pain, and stiffness, especially if you have a history of tick exposure or previously had Lyme disease. This test helps confirm whether Lyme bacteria are causing your joint symptoms.

Reference range

Negative: No antibodies to Borrelia burgdorferi detected. Positive: Antibodies to specific B. burgdorferi proteins detected, indicating exposure. Results interpreted per CDC criteria for Western blot interpretation, requiring at least 5 of 10 IgG bands or 2 of 3 IgM bands.N/A

Specimen: fluid

No special patient preparation required. Synovial fluid collection requires arthrocentesis performed by a qualified healthcare provider under sterile conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is primarily used to diagnose Lyme arthritis, which occurs in approximately 60% of untreated Lyme disease patients. A positive immunoblot in synovial fluid indicates that the Lyme disease bacterium has spread to the joint, helping guide appropriate antibiotic treatment. The test is highly specific for Lyme disease when interpreted correctly, but should always be combined with clinical symptoms and history.

Results are reported as positive, negative, or indeterminate based on the presence of specific antibody bands. A positive result typically shows reactivity to certain bacterial proteins (such as OspC or flagellin), while a negative result suggests no evidence of Lyme infection in the joint. Indeterminate results may require repeat testing or additional clinical evaluation.

Frequently asked questions

How is synovial fluid obtained?
A doctor will insert a thin needle into the affected joint (most commonly the knee) to withdraw a small amount of synovial fluid. This procedure is called joint aspiration or arthrocentesis. The area will be cleaned and numbed with local anesthetic to minimize discomfort.
Is this test painful?
The joint aspiration may cause brief discomfort or pressure, but the area is typically numbed with local anesthetic. Some patients may experience mild soreness or swelling at the injection site for a day or two after the procedure.
How long does it take to get results?
Immunoblot testing is a specialized procedure that usually takes several days to complete. Results are typically available within 5-10 business days, depending on the laboratory.
What does a positive result mean?
A positive result indicates that antibodies against Borrelia burgdorferi were detected in your joint fluid, suggesting that Lyme disease is likely causing your joint inflammation. This helps confirm the diagnosis of Lyme arthritis and guides treatment decisions, typically involving a course of antibiotics.
Can I have joint symptoms without a positive test?
Yes, it is possible. Some patients with Lyme arthritis may have negative immunoblot results due to early infection, prior antibiotic treatment, or other factors. Your doctor will consider your symptoms, medical history, physical findings, and possibly other tests (such as blood Lyme disease testing) to make a final diagnosis.
Do I need to fast before this test?
No fasting is required for this test. However, you should inform your doctor about any medications, supplements, or herbal remedies you are taking, as some may affect test results or joint fluid analysis.
  1. 1
    Lyme Disease - Diagnosis and Treatment | CDCSource
  2. 2
    Lyme Disease | Johns Hopkins MedicineSource
  3. 3
    Lyme Arthritis | rheumatology.orgSource

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