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IgG Antibody to Borrelia burgdorferi (Lyme Disease Antibody)

Published: August 9, 2026Updated: August 15, 2026

This test measures antibodies in your blood that your immune system produces in response to *Borrelia burgdorferi*, the bacterium responsible for Lyme disease. It helps diagnose infections caused by tick bites.

Quick summary

["Detects past or current Lyme disease exposure through antibody presence."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
49183-7
Short code
COX2G
Synonyms
C burnet Ph2 IgG Titr Fld
Category
chemistry
Sample
serum
Container
Red-top serum separator tube (SST) or plain red-top tube; transfer serum to sterile cryovial for body fluid specimens
Units
N/A
Ref low
2
Ref high
4
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Indirect Immunofluorescence Assay (IFA)
CPT
86638
SNOMED
313681003
Specimen volume
1-2 mL serum (minimum 0.5 mL); for body fluid specimens, 2-5 mL depending on fluid type
Stability
Serum stable at 2-8°C for 7 days; frozen at -20°C or below for up to 30 days. Avoid repeated freeze-thaw cycles. Body fluid specimens should be processed within 24 hours of collection when stored at 2-8°C.
Hemolysis max
200
Lipemia max
100
Icterus max
40
TAT
48–168 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like fever, fatigue, joint pain, or a rash (e.g., bull’s-eye rash) after a tick bite, or if you live in an area where Lyme disease is common. It can also be used to check for Lyme disease in people with chronic symptoms like arthritis or neurological issues.

How the Test Works

Blood is drawn, and antibodies against *Borrelia burgdorferi* are detected using an immunoassay method. This test identifies whether your immune system has recognized the bacteria, but it does not confirm an active infection alone—additional testing may be needed.

What to Expect Before the Test

No special preparation is needed. You may eat and drink normally, but let your provider know about any medications or conditions that could affect results (e.g., autoimmune diseases).

What to Expect During the Test

A small needle is used to draw blood from a vein in your arm. You may feel a brief pinch, but it usually takes only a few minutes. You can resume normal activities afterward.

Reference range

Titer < 1:100: Negative - No significant Phase 2 IgG antibodies detected; Titer 1:100 to 1:200: Equivocal/Borderline - Repeat testing in 2-4 weeks recommended; Titer ≥ 1:200: Positive - Suggests past exposure or chronic Q fever infectionN/A

Specimen: serum

No fasting required. No special patient preparation necessary. Patients should inform their healthcare provider of any recent antibiotic use (particularly tetracyclines or fluoroquinolones) as treatment may affect antibody titers. Recent vaccination or immunoglobulin therapy may influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results suggest exposure to *Borrelia burgdorferi*, but they may not always mean an active infection. Early treatment with antibiotics can clear the infection if it’s detected promptly. Chronic symptoms may require further evaluation, including follow-up tests or cultures.

Short name

Lyme Disease IgG Antibody

Frequently asked questions

Can this test detect Lyme disease right after a tick bite?
No. Antibodies take time to develop after infection, so this test is typically used to check for past exposure or chronic symptoms rather than an immediate diagnosis.
What if my test is positive but I don’t have symptoms?
A positive result could mean you were exposed to the bacteria but your immune system cleared it, or you may have a false positive. Your provider will discuss next steps, which may include retesting or additional tests to confirm or rule out Lyme disease.
Does this test replace a physical exam or other tests?
No. This test is a screening tool. Your provider will use it alongside your symptoms, medical history, and possibly other tests (like cultures or PCR) to diagnose Lyme disease accurately.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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 15, 2026. · Read our editorial policy