Anti-Borrelia burgdorferi IgG Antibody (Serum/Plasma) – Immunoassay
This test measures antibodies in your blood to detect exposure to *Borrelia burgdorferi*, the bacterium responsible for Lyme disease.
["Helps diagnose Lyme disease by detecting your immune system’s response to the infection."]
Key facts at a glance
- LOINC
- 48849-4
- Short code
- COXPH2IGA
- Synonyms
- C burnet Ph2 IgA Titr Ser IF
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top vacuum tube without anticoagulant. Gel separator tubes are acceptable.
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Critical range
- — – 200 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunofluorescence assay (IFA) for detection of IgA antibodies against Coxiella burnetii phase 2 antigen
- CPT
- 86638
- SNOMED
- 313319003
- Specimen volume
- 1–2 mL of serum (minimum 0.5 mL)
- Stability
- Serum is stable for 7 days at 2–8°C. For prolonged storage, freeze at -20°C or below for up to 6 months. Avoid repeated freeze-thaw cycles as this may degrade IgA antibodies and produce inaccurate titers.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
What This Test Measures
The test looks for antibodies (IgG) produced by your immune system in response to *Borrelia burgdorferi*. These antibodies develop after infection and can persist for months or years. This test is used to confirm past or current Lyme disease exposure, not to diagnose acute symptoms directly.
How the Test Works
Your blood sample is tested using an immunoassay method to detect specific IgG antibodies against *Borrelia burgdorferi*. If antibodies are found, it suggests your body has encountered the bacterium, though other conditions (like tick bites or cross-reactive infections) may also produce false positives.
When You Might Need This Test
A healthcare provider may recommend this test if you have symptoms like rash (erythema migrans), joint pain, neurological issues, or a history of tick exposure. It’s often used after early-stage Lyme disease symptoms or in cases where early treatment wasn’t received.
What to Expect Before the Test
No special preparation is needed. You’ll have a blood draw, typically from your arm, and the sample will be sent to a lab for testing. Results may take several days to weeks, depending on lab processing times.
Reference range
Negative: <1:50; Equivocal: 1:50–1:100; Positive: ≥1:200. Titers of ≥1:200 suggest chronic Q fever infection. Reference ranges vary by laboratory; results should be interpreted alongside phase 1 antibody titers and clinical findings.N/A
No special patient preparation required. Serum should be collected by standard venipuncture technique. Patient should be informed that this test detects antibodies to Coxiella burnetii, the causative agent of Q fever, and is commonly used in the evaluation of chronic Q fever and culture-negative endocarditis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results indicate past or current *Borrelia burgdorferi* exposure but do not always correlate with active Lyme disease. Early treatment with antibiotics is critical for resolving symptoms. False positives can occur, so clinical correlation with symptoms and other tests (like PCR or culture) is often needed for diagnosis.
Short name
Anti-Borrelia IgG
Frequently asked questions
How long do I need to wait for results?
Can I get this test if I’ve already been treated for Lyme disease?
What if my test comes back positive but I don’t have Lyme disease symptoms?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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