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Anti-Borrelia burgdorferi IgG Immunoassay (Serum)

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

This blood test measures the presence of antibodies to *Borrelia burgdorferi*, the bacterium responsible for Lyme disease. Antibodies develop after infection and can help confirm a past or current Lyme disease exposure.

Quick summary

["This test helps diagnose Lyme disease by detecting immune system responses to the infection."]

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

Key facts at a glance

LOINC
7829-5
Short code
COXPH1
Synonyms
C burnet Ph1 IgG Ser-aCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube; red blood cells should be separated from serum within 2 hours of collection
Units
N/A
Ref low
0
Ref high
1
Critical range
— – 800 N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Immunofluorescence Assay (IFA) - the gold standard serological method for detecting and titrating Coxiella burnetii phase-specific antibodies
CPT
86638
SNOMED
122450008
Specimen volume
1-2 mL serum (minimum 0.5 mL); for paired acute and convalescent samples, 2-3 mL total recommended
Stability
Stable at room temperature for 8 hours, refrigerated (2-8°C) for 7 days, frozen at -20°C or below for long-term storage (up to 6 months). Avoid repeated freeze-thaw cycles
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

What This Test Measures

The test detects IgG antibodies specific to *Borrelia burgdorferi*, a bacterium transmitted through tick bites. These antibodies are produced by your immune system in response to infection. The presence of these antibodies suggests exposure to the bacterium, which can indicate Lyme disease or past infection.

How the Test Works

A small blood sample is drawn and analyzed using an immunoassay method. This test identifies IgG antibodies that bind to *Borrelia burgdorferi* antigens, confirming exposure. Results are qualitative (positive or negative) rather than quantifying antibody levels.

When You Might Need This Test

Your healthcare provider may recommend this test if you have symptoms of Lyme disease (e.g., fever, rash, joint pain) after a tick bite or in areas where Lyme disease is common. It may also be used to monitor treatment progress or assess past exposure.

Symptoms and Risk Factors

Lyme disease symptoms can include a bullseye rash, flu-like illness, fatigue, or joint/muscle pain. Risk factors include living in or visiting tick-endemic regions, outdoor activities, or recent tick exposure. This test is not diagnostic for active Lyme disease alone but supports broader evaluation.

Reference range

Negative: <1:16; Equivocal: 1:16 to 1:32; Positive: ≥1:64. Phase 1 IgG antibody titers ≥1:800 are highly suggestive of chronic Q fever infection, while titers between 1:100 and 1:800 may indicate past exposure or early chronic infectionN/A

Specimen: serum

No fasting required. Patients should inform their healthcare provider of any recent antibiotic use, particularly doxycycline, as this may affect antibody titers. Acute and convalescent serum samples (2-4 weeks apart) are recommended for seroconversion assessment

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-Borrelia IgG

Frequently asked questions

Why might my test results be positive if I don’t have symptoms?
You could have a past infection that resolved without symptoms, or the test may detect antibodies from a previous exposure. Some people naturally develop these antibodies without illness. Always discuss symptoms and medical history with your provider.
Can this test be used to confirm Lyme disease right away?
No, this test alone cannot confirm Lyme disease. It helps assess exposure but requires clinical correlation (symptoms, tick exposure, other tests). Early Lyme disease may not show antibodies yet, so follow-up testing may be needed.
What if my test is negative but I still have Lyme disease symptoms?
Negative results can occur if testing was done too early (before antibody development) or if the infection was treated. Repeat testing or additional tests (e.g., ELISA, Western blot) may be recommended. Consult your provider for a tailored evaluation.
  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 16, 2026. · Read our editorial policy