Bburgdoriggindexsercsfacnc
This test measures IgG antibodies against Borrelia burgdorferi, the bacteria that causes Lyme disease, using blood or spinal fluid samples.
{"The test detects your immune system's response to Lyme disease bacteria","IgG antibodies appear 2-4 weeks after infection and indicate a later stage of infection","Results are reported as an index value to help determine if you have been exposed to Lyme disease","Testing both blood and spinal fluid may be done when neurological symptoms are present","A positive result suggests past or current exposure, but your doctor will interpret it with your symptoms"}
Key facts at a glance
- LOINC
- 47304-1
- Short code
- LYMEG
- Synonyms
- B burgdor IgG Index Ser+CSF-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum: Red-top or serum separator tube (SST) for serum collection; CSF: Sterile, leak-proof, screw-cap plastic collection tube (tube #2-4 typically preferred for cell counts and chemistry)
- Units
- N/A
- Ref low
- 0
- Ref high
- 0.9
- Critical range
- — – 1.1 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Two-tier testing: First tier - Enzyme Immunoassay (EIA) or Immunofluorescence Assay (IFA); Second tier (if first tier positive/equivocal) - Western Blot for IgG antibodies
- CPT
- 86618
- SNOMED
- 416981003
- Specimen volume
- Serum: 1-2 mL minimum; CSF: 1-2 mL minimum for antibody index calculation (paired serum and CSF specimens required for accurate interpretation)
- Stability
- Serum: Stable at room temperature for 8 hours; refrigerated (2-8°C) for 7 days; frozen (-20°C or below) for up to 30 days. CSF: Stable at room temperature for 4 hours; refrigerated (2-8°C) for 7 days; frozen (-20°C) for longer storage. Avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 50
- Icterus max
- 25
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The Borrelia burgdorferi IgG Antibody test checks for IgG antibodies in your blood (serum) or cerebrospinal fluid (CSF). IgG antibodies are proteins made by your immune system to fight infections. When you are infected with Borrelia burgdorferi—the bacterium that causes Lyme disease—your body produces these antibodies. This test helps determine if your body has been exposed to the Lyme disease bacteria.
How is the test performed?
For a blood test, a healthcare provider will draw a small sample of blood from a vein in your arm. For CSF testing, a procedure called a lumbar puncture (spinal tap) is needed to collect fluid from around your spinal cord. The sample is then sent to a laboratory where technicians look for IgG antibodies specific to the Lyme disease bacteria.
What do the results mean?
Results are given as an 'index' value. A higher index suggests stronger evidence of exposure to Lyme disease bacteria. Your doctor will consider the test result along with your symptoms, medical history, and any recent tick bites to determine if you have Lyme disease. It's important to note that IgG antibodies develop 2-4 weeks after initial infection, so the test may not detect very early Lyme disease.
Why might both blood and CSF be tested?
Testing both blood and CSF is typically done when neurological symptoms of Lyme disease are present, such as severe headaches, facial palsy, or meningitis. Comparing antibody levels in both fluids can help determine if the infection has spread to the nervous system.
Reference range
Index value interpretation (varies by laboratory/method): Negative: <0.90; Equivocal: 0.90-1.09; Positive: ≥1.10. The antibody index (AI) for CSF is calculated as (CSF IgG/specimen total IgG) / (Serum IgG/serum total IgG); AI >1.5 suggests intrathecal antibody production consistent with neuroborreliosisN/A
No special preparation required. Fasting is not necessary. Patient should inform clinician of recent antibiotic use, tick exposure history, duration of symptoms, and prior Lyme disease vaccination (if applicable). For CSF specimen, lumbar puncture is required and performed by qualified healthcare provider
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
Can this test tell me if I have an active Lyme disease infection?
What is the difference between IgG and IgM testing?
Is a lumbar puncture (spinal tap) safe?
Sources
- 1
- 2
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.
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 15, 2026. · Read our editorial policy